^{page 346 note 1} See Charts in a Summary of the Scientific Results obtained at the sounding, dredging, and trawling Stations of H.M.S. Challenger, 1895.

^{page 346 note 2} This view as to the origin of these continental rocks is supported by the facts that D'urville found a rocky islet off Adelie Land, to be composed of gneiss and granite, that Wilkes found, on an iceberg in the same locality, boulders of red sandstone, and that Mr Borchgrevink, who landed at Cape Adair from the whaler “Antarctic” in 1895, brought away fragments of mica-schists and microcline-granite, with quartz, felspar, tourmaline, and garnets.

^{page 348 note 1} See Murray, , “The Renewal of Antarctic Exploration,” Geogr. Journ., vol. iii. p. 17, 1894Google Scholar, with map of isobars and winds.

^{page 349 note 1} Thus we find that at Station 156, 1975 fathoms, the surface temperature was 33°·5, the temperature at 100 fathoms was 31°·9, and at 150 fathoms 34°, and below the depth of 150 fathoms the thermometer came up, showing on the maximum side 34°, and on the minimum side 31°·9; hence it is impossible to say what the precise temperature of the sea was below 150 fathoms: all that can be asserted is that it ranged between 34° and 31°·9.

^{page 350 note 1} See Challenger Report, Summary of Results, First Part, passim.

^{page 353 note 1} Axinella erecta is a very variable species.—(Ridley and Dendy, Zool. Chall. Exp., part 59, p. 182.)

^{page 353 note 2} Although the different species of Cladorhiza vary very much in external form, yet the different modifications of the main skeleton, upon which the external form of the sponge depends, are easily derivable from one common primary type, and afford interesting instances of adaptation.—(Ridley and Dendy, Zool. Chall. Exp., part 59, p. 86.)

^{page 353 note 3} Cladorhiza moruliformis is a form of the very greatest interest, and affords a good example of radial symmetry in a Monaxonid Sponge. It was a question with us whether or not this species should form the type of a new genus, but we finally decided not, as no essential changes are necessary to derive it from the more typical species. … It is, of course, by no means impossible that perfect specimens of Cladorhiza moruliformis may have a branching stem with a head at the end of each branch.—(Ridley and Dendy, Zool. Chall. Exp., part 59, pp. 91, 92.)

^{page 353 note 4} In the arrangement of its skeleton Cladorhiza tridentata stands quite alone in the genus, and as this is generally such a good guide, it seems very doubtful whether it ought to be admitted as a Cladorhiza, but for the sake of convenience we shall retain it here for the present, placing it at the end as a doubtful species.—(Ridley and Dendy, Zool. Chall. Exp., part 59, p. 96.)

^{page 353 note 5} Esperella mammiformis is a very beautiful little species, and affords another good example of a deep-sea sponge with a definite external form.—(Ridley and Dendy, Zool. Chall. Exp., part 59, p. 63.)

^{page 353 note 6} Several of the species of the genus Esperiopsis are remarkable for their well-defined external forms, which serve as excellent guides by which to separate them from one another and from others of the genus. … The distribution of the genus Esperiopsis is very wide, both vertically and horizontally, but it appears to prefer deep water in temperate or boreal seas.—(Ridley and Dendy, Zool. Chall. Exp., part 59, p. 77.)

^{page 353 note 7} Esperiopsis profunda is interesting on account of the great depth (1600 fathoms) from which it was obtained, and with this must again be associated the presence of a definite external form.—(Ridley and Dendy, Zool. Chall. Exp., part 59, p. 81.

^{page 354 note 1} The genus Meliiderma stands in much the same relation to Chondrocladia as does Axoniderma to Cladorhiza, having, like Axoniderma, developed a special spicule for external defensive purposes. The form of the extra spicule is, however, totally different in the two cases; and in Meliiderma it appears to be confined to the stalk, while in Axoniderma it is most abundant in the body of the sponge. In both these cases it is very difficult to say whether the extra spicule ought to be classed amongst megasclera or microsclera; for the sake of convenience both will here be regarded as microsclera, though standing on quite a different footing from other microsclera. The form of the extra microsclera in Meliiderma stipitata is as yet unparalleled. From their resemblance to spears or darts we have derived the generic name. … Only one perfect specimen of this sponge and one damaged one are in the collection; in both of these the stalk is encrusted by a thin, yellow, velvet-like layer of the densely packed, spear-like spicules. At first we thought that these spicules belonged to some foreign encrusting sponge, and hence no mention of them was made in our Preliminary Report, but subsequent examination has convinced us that they are proper to the species; the fact of their occurring in both specimens being strong evidence in favour of this view. An interesting point about the sponge is the position in which the embryos develop. In the specimen which we cut open a number of round yellow bodies were found, each enclosed in a membranous capsule around which the chelate spicules were lying in very great numbers. These embryos were placed in a zone of tissue occupying about the centre of the spherical head, and lying immediately above the expanded termination of the stalk, between the bands of spiculo-fibre which radiate from it; this being obviously the position of greatest security.—(Ridley and Dendy, Zool. Chall. Exp., part 59, pp. 102, 103.)

^{page 354 note 2} The genus Stylocordyla still stands aloof from all other Suberitidæ in its remarkable spiculation, though, as regards external form, the old distinction embodied in the term Stylocordyla no longer holds good, for similar stipitate forms are found to occur in the genus Suberites. … The external form of this sponge is very variable. Schulze, as well as Carter, has already noticed that the head in young forms is more or less round; we have to notice below a variety in which the head is globular even in the adult.—(Ridley and Dendy, Zool. Chall. Exp., part 59, pp. 222, 223.)

^{page 354 note 3} The genus Thenea is the characteristically deep-water genus of the Tetractinellida, the shallowest water from which it has yet been recorded being 78 fathoms, the deepest 1913 fathoms.—(Sollas, Zool. Chall. Exp., part 63, p. 404.)

^{page 354 note 4} It is a striking fact that [among the Hexactinellida] the Asconematiclæ, which occur somewhat abundantly in the south temperate zone, and likewise in the north, are represented in the tropics only by a single species.—(Schulze, Zool. Chall. Exp., part 53, p. 449.)

^{page 354 note 5} Aulocalyx irregularis appears to be widely distributed, since it was found both in the north and south temperate zones.—(Schulze, Zool. Chall. Exp., part 53, p. 450.)

^{page 354 note 6} Caulophacus latus was found in the south temperate zone, the other species, Caulophacus elegans, far removed in the northern region.—(Schulze, Zool. Chall. Exp., part 53, p. 450.)

^{page 355 note 1} The axis in the imperfect specimen dredged of this deep-sea form [Callozostron mirabilis] is about 280 mm. in length, it is extremely flexible, and nearly 20 mm. in widest diameter. The colony strongly reminds one at first sight of some gigantic Annelid. … It seems probable that this species lived prostrate in the mud, and possibly there may have been some power of expansion and contraction in the colony. It was dredged in the most southern station reached by the Challenger.—(Wright and Studer, Zool. Chall. Exp., part 64, pp. 48, 49.)

^{page 355 note 2} It follows from all these facts that the simpler forms of the Pennatulida, especially those with sessile polyps, inhabit great depths. The presence of their less complex representatives in deep water has also been shown in other invertebrate groups. These simpler forms are probably also the oldest, and may be regarded as the last remnants of an extinct primary creation. The Protoptilidæ and the Umbellulidæ are the principal representatives of these old forms, and of these two families especially the Challenger Expedition has discovered a large number of species with a wide distribution. This addition to our knowledge makes it possible to gain a better insight than formerly into the development of the whole group.—(Kölliker, Zool. Chall. Exp., part 3, p. 39.)

^{page 355 note 3} The five specimens of Umbellula carpenteri showed a very interesting gradation from a bilateral to an apparently irregular arrangement of the polyps. One specimen had one terminal and two lateral polyps; another specimen had four polyps, all lateral; a third specimen had one terminal polyp, two lateral on the right and one only on the left side; in a fourth there were eight polyps, of different sizes, so disposed that they formed a rosette surrounding a, small dorsal area of the rachis of a stellate form, but amongst these polyps the terminal one was easily recognisable, as the axis ended in its base, and the other seven could be interpreted as lateral polyps arising from a shortened rachis; the fifth specimen finally showed eight polyps, arranged in the form of a rosette, and surrounding like a cup a ninth middle polyp, but this was not the terminal one in which the axis ended, one of the eight had this signification.—(Kölliker, Zool. Chall. Exp., part 3, pp. 23–4.)

^{page 355 note 4} The varying character of the deep-sea fauna leads us to the question, has life in the great depths a visible influence on the organisation of the Actiniæ? This influence can be distinctly recognised in many forms, and is shown by the nature of the tentacles which have undergone retrograde formation, and are transformed first into tubes, and afterwards into simple openings in the oral disk. In Paractis tubulifera (1875 fathoms) the tentacles have the same constitution as in the majority of Actiniæ, except in one point, that the terminal opening, which is usually small or entirely wanting, gapes widely. In Polysiphonia tuberosa (565 fathoms) the tentacles have become short, slightly movable, wide-mouthed tubes; in Sicyonis crassa (1600 fathoms) they are small wart-like rings, and in Polystomidium patens (1825 fathoms) and Polyopis striata (2160 fathoms) the walls have almost entirely disappeared, so that the terminal opening forms a fissure in the oral disk, the last remains of the tentacle being represented by a circular margin surrounding the fissure, and so we come finally to the genus Liponema (1875 fathoms), in which the points at which the tentacles were actually placed are merely indicated by openings in the oral disk. Of the twenty-one forms from 500 to 3000 fathoms here described, no less than six species have therefore undergone modifications of the tentacles in the same sense, whilst it has never been observed in a single one of the forms of the coast fauna, which greatly exceed the deep-sea fauna in number. … There is another point in the mode of life of the deep-sea Actiniæ which seems to me to favour the transformation of the tentacles into tubes and openings. The nutriment of the deep-sea animals probably consists chiefly of material which is already disintegrated, and of a soft nature when obtained. The animals often ingest sand, impregnated with nutriment, from which they extract what is digestible; at least I have repeatedly found the interior of the deep-sea Actiniæ full of mud. In such a mode of nutrition the long prehensile tentacles would not be of the same use as they are in the littoral Actiniæ, which lie in wait for booty, whilst on the other hand it would be a decided advantage to the animals to be furnished with numerous inhalent tubes and openings through which they can absorb semi-liquid nourishment. This then is the advantage of the stomidia and tubular tentacles. The retrograde formation of the tentacles is by no means the only point to be taken into consideration in the varying character of the deep-sea Actiniæ, the position of the septa being equally important. The arrangement of the septa typical of the Hexactiniæ is only present in thirteen genera, among which I reckon Ophiodiscus and Polystomidium, in which we meet with the differentiation of muscular and genital septa which is otherwise unknown, and the genera Stephanactis and Amphianihus, in which we find some approach to the Antipatharia. The other four genera differ from one another as well as from the Hexactiniæ in the arrangement of the septa. They swell the number of the varying forms represented in shallow water by the Zoantheæ, Ceriantheæ, and Edwardsiæ, and therefore seem to indicate that the diversity in the structure of the Anthozoa was formerly much greater than it is at present, and that the remains of this diversity have been more extensively preserved in the depths of the sea than in the shallow waters. In this way we can recognise peculiarities in deep-sea Actiniæ which are common to the whole deep-sea fauna.—(Hertwig, Zool. Chall. Exp., part 15, pp. 132–134.)

^{page 356 note 1} The tentacles in Liponema multiporum have undergone retrograde formation to a greater extent than in any other Actinia, as there are not the smallest remains of their walls, while in Polyopis these can still be recognised as thickened ridges surrounding the openings.—(Hertwig, Zool. Chall. Exp., part 15, p. 129.)

^{page 356 note 2} Whilst the majority of Actiniæ, especially those from great depths, form a short column, and are frequently flattened into a disk, the body form of Porponia elongata, from 2600 fathoms, approximates that of the elongated Cerianthidæ. In both specimens examined the body, though contracted, was twice as long as high. It is broadest in the region of the oral disk, below which it becomes a little narrower, and then becomes broader again at the pedal disk, by which it is firmly attached to the bottom.—(Hertwig, Zool. Chall. Exp., part 15, p. 125.)

^{page 356 note 3} Sicyonis crassa is one of the most interesting Actiniæ dredged from great depths, both on account of the constitution of the tentacles and of the arrangement of the septa.—(Hertwig, Zool. Chall. Exp., part 15, p. 98.)

^{page 356 note 4} The single specimen of Tealiddum cingulatum, which was taken attached to a stone from a depth of 1800 fathoms, belongs to the smallest forms among the Challenger material. It is so strongly contracted that the wall closes over the entrance to the oral disk till only a small opening is left.—(Hertwig, Zool. Chall. Exp., part 15, p. 51.)

^{page 356 note 5} Baihyactis symmetrica was dredged by the Challenger in all parts of the world. It varies very much in size and appearance, the smallest specimens obtained measuring 3 mm. and tbe largest 40 mm. in diameter; the increase in size being evidently not a matter of age and growth as of different development under different conditions. … The inspection of a long series of specimens leaves no doubt as to the identity of the large specimens with the small ones. The very large specimens are excessively thin and fragile, and only a small percentage of them were obtained in an unbroken condition. … The larger specimens vary in very much the same manner as the smaller; some have the margins of their septa fused for long distances at their points of junction; others show little fusion of the septal margins. In some specimens the fusion of the septal margins is very irregular, in one a spongy outgrowth is developed from the coverings of one of the deltas. In some of the largest specimens there is scarcely any trace of a columella; in others there is a large oval one, composed of a membranous expansion, through which the spines project. … After tabulating all the occasions on which this coral was dredged, I cannot succeed in establishing any relation between the size of the specimens dredged, and the conditions of depth, bottom, or temperature. No large specimen was dredged in less than from 200 to 360 fathoms, but from one of these depths a broken specimen, which must have measured more than 30 mm. in diameter, was obtained. Small, apparently adult, specimens of the stouter variety, measuring only 9 mm. in diameter, were dredged from such depths as 2440 fathoms on several occasions. The greater number of very large specimens were obtained from deep water, many being brought up at one haul of the dredge, as at Station 147, in the South Indian Ocean, where twenty or thirty specimens were obtained from 1600 fathoms, curiously enough, all of them large, no young ones being found amongst them. Bathyactis symmetrica was found to have a wider range than any other deep-sea coral, being, in fact, apparently universally distributed in deep water. It has also a wider range in depth than any other animal, occurring in 30 fathoms off Bermuda, and in the East Pacific Ocean at a depth of 3 miles. It was dredged abundantly at Station 244, 2900 fathoms, the specimens being large and in full vigour, full of ripe ova. Some specimens appear as if they had been broken and had reunited, or possibly they were when obtained in the act of splitting up into fragments, or have a tendency to do so.—(Moseley, Zool. Chall. Exp., part 7, pp. 186–188.)

^{page 357 note 1} I have founded this genus [Leptopenus] to contain two very remarkable corals, dredged in deep water, which are so fragile that it is astonishing that they arrived at the surface in such good preservation as that in which they were obtained. The two species differ markedly from one another, but have so many fundamental agreements that they must evidently be placed in the same genus. They are evidently closely related to the Stephanophyllias, but their corallum is so perforate as to be reduced to a mere lace-work. No corals immediately like them appear to have been procured before, or since, either in the recent or fossil condition. Specimens belonging to the genus were dredged on four occasions, all from deep water (over 1500 fathoms), and all in the Southern Hemisphere.—(Moseley, Zool. Chall. Exp., part 7, p. 205.)

^{page 357 note 2} The vast depth from which Cryptolaria abyssicola has been dredged (2600 fathoms) gives it a special interest, which is greatly enhanced by the fact that it affords one of the very few instances as yet known in which the gonosome of Cryptolaria has been detected. The scattered instead of distichous disposition of the hydrothecre is a peculiar and exceptional character.—(Allman, Zool. Chall. Exp., part 70, p. 40.)

^{page 357 note 3} The genus Halisiphonia is represented in the Challenger collection by a single species, which presents many points of special interest. … The very long tubular hydrothecse gradually passing into their long peduncles confer on this remarkable species [Halisiphonia megalotheca] an aspect as striking as it is distinctive. … The enormous depth of 2600 fathoms from which both Halisiphonia megalotheca and Cryptolaria abyssicola were obtained has much significance, in connection with the fact that in both species the gonangia are present, Halisiphonia megalotheca affording the only known instance, and Cryptolaria abyssicola one of the very few, in which any part of the gonosome has been observed in these genera.—(Allman, Zool. Chall. Exp., part 70, p. 31.)

^{page 357 note 4} In discussing the distribution of Antedon and Actinometra, the two principal genera of Comatuke, it must be remembered that each of them, but especially Antedon, contains a very large number of species, and they should be considered for this purpose to represent subfamilies rather than genera. Thus, for example, the name Antedon is now given to all endocyclic Comatulse with the basals metamorphosed into a rosette, and five rays bearing ten or more arms, just in the same way as the name Echinus was originally used for a variety of regular Urchins, which have now received different generic names. The difference between the tiny ten-armed Antedon abyssicola inhabiting depths of 3 miles and upwards, and the littoral Antedon elegans, Antedon multiradiata, or Antedon regalis, is no doubt very considerable at first sight; but there are so many intermediate links between the simple and the complex forms, that no hard and fast generic lines can be drawn.—(P. H. Carpenter, Zool. Chall. Exp., part 60, p. 31.)

^{page 357 note 5} This little species [Antedon abyssicola] is one of very considerable interest, apart altogether from the peculiarities of its calyx, for it is the only Comatula yet found at a greater depth than 2000 fathoms. Bathycrinus, and perhaps also Hyocrinus, extend down to 2400 fathoms; Promachocrinus and Thaumatocrinus occur at 1800 fathoms, but with the exception of Antedon abyssicola, no other Comatulce have been found below 1600 fathoms, at which depth (Station 147) Antedon abyssorum, Antedon bispinosa, and Antedon remota were obtained. Antedon abyssicola has been dredged, however, at two Stations, one (Station 160) shortly before the Challenger reached Melbourne, where the depth was 2600 fathoms, and the other in the deepest part of the North Pacific at 2900 fathoms (Station 244). Antedon abyssicola thus resembles Antedon alternata in occurring at widely separated localities in the abyssal region, and it has some points of resemblance with the younger individuals of this type.—(Carpenter, Zool. Chall. Exp., part 60, pp. 191–2.)

^{page 358 note 1} Antedon bispinosa has such very definite characters that it is not likely to be confounded with any other. The spiny calyx and the double row of long hook-like spines along the arms distinguish it very clearly. … It is rather a robust species for such a considerable depth (1600 fathoms). But the sacculi are poorly developed, as is so often the case in the abyssal Comatulæ.—(Carpenter, Zool. Chall. Exp., part 60, p. 116.)

^{page 358 note 2} Bathycrinus ranges through a greater number of degrees of latitude than any other stalked Crinoid, even Rhizocrinus; and it is only surpassed in this respect by the ubiquitous Antedon. Bathycrinus carpenteri was found by the Norwegian North Sea Expedition as far north as 65° 55′ N. lat.; while Bathycrinus aldrichianus was twice met with by the Challenger in the Southern Ocean beyond the parallel of 46° S. lat. In the intervening Atlantic Ocean have been found Bathycrinus gracilis (Bay of Biscay) and Bathycrinus campbellianus (just north of the equator); while other examples of the genus were dredged by the “Talisman” in the Atlantic at a depth of from 2000 to 2380 metres (1200 fathoms). It is distinctly an abyssal type, ranging from 1050 to 2435 fathoms. The only Crinoids which have been found at greater depths than the latter are two species of Antedon.—(Carpenter, Zool. Chall. Exp., part 32, p. 237.)

^{page 358 note 3} As now classified the species [of the genus Freyella] present a remarkable similarity of general facies, and the comparatively small amount of morphological plasticity exhibited by the genus is extraordinary, considering the wide geographical area over which it is distributed. The bathymetrical range is also remarkable, extending from the commencement of the continental zone to the greatest depth at which starfishes have been found.—(Sladen, Zool. Chall. Exp., part 51, p. 615.)

^{page 358 note 4} The dredgings of the Challenger Expedition have now shown that Hymenaster possesses a world-wide distribution in deep waters, and that the genus exhibits a remarkable amount of morphological plasticity, no less than twenty-four species being now known. The bathymetrical range of the genus is also remarkable, as, with the exception of the type form (Hymenaster pellucidus), which ranges from 70 to 1539 fathoms, all the species are confined to the abyssal zone. One, Hymenaster infernalis, extends to 2900 fathoms, the greatest depth at which starfishes have hitherto been found; and four other species occur in depths greater than 2000 fathoms. … The general facies of the type appears to be one of great antiquity. This, however, is riot the place to discuss, as I should desire, the archaic relationships of existing Asterids; and I would therefore now only briefly direct attention to the remarkable resemblance and, in many respects, apparent similarity of general character, which exist between Hymenaster and the recently described Loriolaster of Stürtz from the Lower Devonian slatés of Bundenbach.—(Sladen, Zool. Chall. Exp., part 51, p. 492.)

^{page 359 note 1} This species [Porania antarctica] may be distinguished from the rather closely related northern P. pulvillus, Müller, by differences in the ambulacral spines, and in the number and character of the marginal spines.—(Smith, E. A., Phil. Trans., vol. 168, p. 276Google Scholar.

^{page 360 note 1} In the genus Pourtalesia proper, as I have retained it here, there are two groups of species readily distinguished from the character of the test; these I was at first inclined to separate into distinct sub-genera on comparing such extreme forms as Pourtalesia miranda, laguncula, and phiale with such forms as Pourtalesia ceratopyga and rosea. The former group is distinguished by the extreme tenuity, almost transparency, of the test and its more or less bottle-shaped outline, while the latter group contains species with a flattened test, a triangular outline from above, and a comparatively thickened test.—(Agassiz, Zool. Chall. Exp., part 9, pp. 132–3.)

^{page 360 note 2} The limits which have been assigned to the genera closely allied to Schizaster are very unsatisfactory, and the generic characters by which different species are assigned to these genera or sub-genera pass so gradually one into the other, not merely among the recent species, but especially when we come to include the fossil species, that the task of properly limiting them appears hopeless, although these characters are convenient as sub-divisions according to which we may associate groups of species.—(Agassiz, Zool. Chall. Exp., part 9, p. 200.)

^{page 360 note 3} The three species above mentioned, viz., Holothuria lactea, Holothuria thomsoni, and Holothuria murrayi, form a group by themselves among the numerous representatives of the genus Holothuria, and it is very probable that they may be properly placed in a new genus, or, at least, in a sub-genus. Indeed, Holothuria thomsoni differs so strikingly from all forms hitherto known that I should not hesitate to refer it to a new genus if I had not had the opportunity of examining the two other forms, which evidently form a transition to the true Holothuriæ. Holothuria thomsoni is distinguished by twelve tentacles, and its variety by fifteen, numbers of tentacles hitherto unknown in any species of Holothuria. That which seems to be common to the three species above mentioned and their varieties is, firstly, the conformation of the calcareous deposits, and secondly, the peculiarity that the pedicels of the two lateral ventral ambulacra either form a simple distinct row, or that, if they are more numerous and crowded, some of them are larger and more or less distinctly arranged in a row along each side of the body.—(Théel, Zool. Chall. Exp., part 38, p. 187.)

^{page 362 note 1} Bairdia is a widely dispersed genus, attaining, apparently, its greatest development in the tropical and southern seas, in dredgings from which regions the number of specimens of Bairdiæ not unfrequently exceeds that of all other Ostracoda together; the individuals, however, though numerous, are usually found to belong in each gathering to one, or at most two, predominant species.—(G. S. Brady, Zool. Chall. Exp., part 4, p. 48.)

^{page 362 note 2} The genus Cythere includes probably nearly as many species, recent and fossil, as all the remaining genera [of Ostracoda] put together, the number assigned to it in this monograph being 83 out of a total of 221. But though in its present form excessively unwieldy, it seems impossible, without a more perfect knowledge than we yet possess of the variations of anatomical structure in the several species, either to form useful sub-genera, or to separate from the main group any true generic types.—(Brady, Zool. Chall. Exp., part 4, p. 62.)

^{page 362 note 3} This species [Krithe producta] is either a cosmopolitan one, and very variable as to shape, or the figures given under its name, which are fairly representative of many different examples, must belong to other undescribed species. I prefer, however, to consider them as forms of Krithe producta, the variations observable in a large series of specimens being almost countless, and, as I think, in many cases fairly referable to differences of age, sex, or race.—(Brady, Zool. Chall. Exp., part 4, p. 114.)

^{page 362 note 4} Scalpellum seems to be the only genus of Cirripedia which is often met with in the great depths of the ocean. This strikingly coincides with the common occurrence of this genus in the fossil deposits, especially in secondary strata (Cretaceous period). … The great number of species in this genus suggested the idea of dividing it into smaller genera. After careful examination this idea, however, has been given up, as all the species in essential characters correspond as closely, even more closely, with one another than in any other genus of Cirripedia. Nor has it been an easy matter to arrange the species in a natural way.—(Hoek, Zool. Chall. Exp., part 25, p. 60.)

^{page 363 note 1} From west to east the genus Lanceola may be considered as ranging round the world, while from north to south a range is shown of more than ninety degrees, to which may be added about thirty degrees northward, since Lanceola clausii was taken in Davis Strait, lat. 72° N. It is remarkable that each of the Challenger specimens was labelled, not, like most of the Hyperina with the word “surface,” but with the number of fathoms of the particular station, indicating that the specimen was supposed to have come from the great depth mentioned. It may be conjectured that the smallness of the eyes and the soft membranaceous character of the integument are connected with residence in the abysses of the ocean, and the latter character perhaps also with a capacity for passing without injury from the bottom to the surface. The pleopods are well developed, so that the animal may be itself a good swimmer, but, to account for the wide distribution of the genus, it may be supposed that the creature often avails itself of extraneous assistance, the retractile claws of the last three pairs of peræopods being well adapted for giving it a firm hold upon animals of much greater size and speed.—(Stebbing, Zool. Chall. Exp., part 67, p. 1317.)

^{page 363 note 2} The range of the genus Phronima as illustrated by the Challenger specimens is between lat. 36° 23′ N. and 50° 1′ S., aud over a space of 223 degrees between long. 13° 5′ W. and 123° 4′ E. Specimens from the Shetland Isles carry the range in latitude up to 60° N. in the Atlantic; Dr Streets extends it to 40° N. in the Pacific; and since Dr Giles has added the Bay of Bengal to so many other localities from which the genus is known, its range from east to west may fairly be considered as extending all round the world.—(Stebbing, Zool. Chall. Exp., part 67, p. 1361.)

^{page 364 note 1} This Schizopod [Eucopia australis] would appear, on the whole, to be a true deep-sea form, ranging, as it does, from a depth of 1000 to 1975 fathoms. It is worthy of remark, however, that the specimen described by Dana was taken from the stomach of a penguin; and, as it cannot be reasonably assumed that any air-breathing animal can descend to the enormous depths stated above, the said form may also be considered as occasionally occurring at a less considerable depth. It would seem, too, that this view is in part corroborated by the statement of the late Dr v. Willemoes-Suhm, who says that in the Atlantic this species is met with at depths ranging from 350 to 2500 fathoms. The late Dr v. Willemoes-Suhm observes concerning this form that “it is the commonest Schizopod of the deep-sea fauna, and seems to enjoy a very wide bathymetrical and geographical distribution.” Indeed its geographical range is quite astounding, for it is met with not only throughout the great depths of the Atlantic, but also in the Antarctic Ocean, the Australian seas, and even in the Pacific, as far north as Japan.—(Sars, Zool. Chall. Exp., part 37, p. 62.)

^{page 364 note 2} All the species belonging to the genus Gnathophausia seem to be well-marked deep-sea forms. The least depth from which specimens have been obtained is 250 fathoms, and the greatest 2200 fathoms. Gnathophausia has never been taken at the surface of the sea; it may therefore certainly be assumed that these Crustacea, notwithstanding their strongly developed natatory organs, never leave the deeper strata of the sea, and that in all probability they have their habitat on the sea-bottom itself. … The genus seems to exhibit a, very extensive geographical distribution, being most probably represented throughout the greater part of the ocean, excepting perhaps the Arctic and Antarctic regions. Thus, species of this genus have been recorded both from the North and South Atlantic, from the Pacific, and from the seas of the Indian Archipelago. The genus may even be reckoned among the European fauna, one of its species having been found by the Trench expedition in the Bay of Biscay.—(Sars, Zool. Chall. Exp., part 37, p. 29.)

^{page 364 note 3} Exclusive of the specimen of Gnathophausia gigas taken in the North Atlantic, west of the Azores, I also found among the material placed in my hands for examination the recently moulted skin of the outer part of the tail of another specimen, apparently belonging to the same species, brought up in the Southern Ocean, between Kerguelen and Australia. Hence the species seems to exhibit a rather extensive geographical distribution, its occurrence in both hemispheres having been ascertained.—(Sars, Zool. Chall. Exp., part 37, p. 35.)

^{page 364 note 4} Of this genus [Pseudomma] three northern species have been recorded; two additional species were met with on the Challenger Expedition, both in the southern hemisphere.—(Sars, Zool. Chall. Exp., part 37, pp. 188–9.)

^{page 364 note 5} The various forms of this genus [Glyphocrangon] can scarcely be considered as being more than varieties of one great type; the specific differences being little else than a greater or less exaggeration of features common to them all.—(Spence Bate, Zool. Chall. Exp., part 52, p. 507.)

^{page 364 note 6} The species of this genus [Hymenodora], like most of the family, are from deep water; only two specimens of one species being taken at a less depth than 2 miles. They are mostly found in mid ocean, on a bottom of mud or ooze: in the Atlantic beneath the equator and as far south as Tristan, and in the Indian Ocean as far south as Kerguelen. Buchholz's specimen was taken at the surface near the pack ice in lat. 78° N. … In the most typical forms the eyes have almost entirely lost their pigment; in some species it is reduced to a brown colour, and in a few it is black, as if the degree of pigmentation was dependent upon variation in depth and degree of light—(Spence Bate, Zool. Chall. Exp., part 52, p. 841.)

^{page 364 note 7} I am inclined to believe that the animals [of the genus Nematocarcinus] live at an average depth of between 300 and 500 fathoms in mid-water.—(Spence Bate, Zool. Chall. Exp., part 52, p. 801.)

^{page 365 note 1} The members of this genus [Munidopsis] have been taken in almost all seas the deep water of which has been explored by the dredge, and they are found at depths varying from about 100 to upwards of 2000 fathoms. The species differ, widely among themselves in the form of those parts which in other Crustacea afford generic characters; and yet it is impossible to effect a natural sub-division, or one which is not founded on a single character to the exclusion of others. It is probable that the loss of sight is compensated by a greater development of the tactile sense, and in some species this is evidenced by the great length of the antennal flagella, which in all probability enable the animal to grope its way about on the bottom.—(Henderson, Zool. Chall. Exp., part 69, p. 148.)

^{page 365 note 2} Whether I am right or not in considering the specimens collected at Stations 146 and 147 (Colossendeis gracilis), Station 298 (Colossendeis media), and Station 325 (Colossendeis brevipes), as three different species can only be ascertained by examining a larger number of specimens than are at my disposal. I can only point out here the great affinity of these different specimens.—(Hoek, Zool. Chall. Exp., part 10, p. 73.)

^{page 366 note 1} Notwithstanding the great distance between the localities where this species [Bathyteuthis abyssicola] and Verrill's Bentheoteuthis megalops [North Atlantic] were captured, it seems quite possible that they may ultimately prove to be the same species (Hoyle, Zool. Chall. Exp., part 44, p. 169).

^{page 366 note 2} In order to include several of the species in the present collection, and to avoid the creation of one or more new genera, I have thought it better in this catalogue so to modify the definition of Bugula as to admit of these, for the most part, new forms being placed in it. … The group, however, as thus made up, includes several apparently distinct types, which will probably at some time be thought of at least sub-generic value. … It may also be observed that the first and second of these groups consist almost exclusively of very deep-water forms, the shallowest being 150 fathoms, whilst the depths from which the other species, included in those groups, were brought up was on the average not less than 2000 fathoms. They would appear therefore to constitute a distinctively abyssal type. … The group affords a striking instance of the comparatively large size and free growth, and at the same time of the extremely delicate structure, characteristic it may almost be said of the Polyzoa that live in the tranquil depths of the ocean.—(Busk, Zool. Chall. Exp., part 30, pp. 37, 38.)

^{page 366 note 3} The species of this multiform and perplexing genus [Gellepora] may be conveniently arranged in two principal more or less artificial sections or groups, characterised primarily by the form of the operculum and secondarily by the general zoarial habit… On the whole the genus would appear to belong to comparatively shallow water.—(Busk, Zool. Chall. Exp., part 30, pp. 191–2.)

^{page 366 note 4} The genus Farciminaria may be regarded emphatically as abyssal; the mean depth at which the species here enumerated occurred being not less than 1500 to 1600 fathoms, or from 450 to 2750 fathoms.—(Busk, Zool. Chall. Exp., part 30, p. 49.)

^{page 366 note 5} Terebratula wyvillii is one of the most interesting species of deep-sea Brachiopoda dredged during the Challenger Expedition. It appears to abound over a wide geographical range, and at depths varying from 1035 to 2900 fathoms. The shell is of such extreme thinness that it is almost transparent; indeed, the valves when separated are really so, and the muscular impressions may be seen through its transparency. It is also exceedingly brittle. It bears much resemblance to several species occurring in the Jurassic and Cretaceous formations and especially so to Terebratula boneti, Zeuschner, from the Kimmeridge of Switzerland, and from which some of the Challenger specimens are scarcely distinguishable, either by size or shape.—(Davidson, Zool. Chall. Exp., part 1, pp. 27, 28.)

^{page 367 note 1} The genus Culeolus has a very considerable horizontal range, two of the species being found in the northern hemisphere, while the remaining four are from the southern. Those in the northern seas are from the temperate zone, while of the southern forms, one is from near the equator, one from between 20° to 30° S. lat., and the remaining two species are from much further south. … Culeolus is a peculiarly deep-water genus, but has a considerable range, viz., from 630 to 2425 fathoms. Five of the species are from upwards of 1000 fathoms, four from over 1500 fathoms, and two from upwards of 2000 fathoms. Thus they all belong to the abyssal fauna.—(Herdman, Zool. Chall. Exp., part 17, pp. 265, 270.)

^{page 367 note 2} Bathydraco antarcticus is clearly allied to Chænichthys; its habitat at a great depth is evidenced by the diminished proportion of earthy matter in the bones of the skull, by its large eyes, wide muciferous channels, and coloration.—(Gunther, Zool. Chall. Exp., part 57, p. 48.)

^{page 367 note 3} In Bathylagus the thinness of the bones, the fragility of the fin-rays, the delicacy of the skin and scales, and the enormously large eyes, seem to be sufficient evidence that these fishes are actually inhabitants of very great depths. These fishes must therefore be entirely dependent for vision on the phosphorescent light which is produced by other abyssal creatures. Not being fish of prey themselves, or only to a slight degree, they would be attracted by the light issuing from the Pediculates and Stomiatids of the deep, and thus fall an easy prey to these fishes.—(Günther, Zool. Chall. Exp., part 57, p. 219.)

^{page 367 note 4} Cyema atrum is extremely interesting, inasmuch as it is still nearer to the Leptocephalid condition than Nemichthys infans. In fact, I had to consider the possibility of its being a less advanced stage of development of that species; however, the minute size of the eye disposes of the idea of genetic affinity.—(Günther, Zool. Chall. Exp., part 57, p. 266.)

^{page 367 note 5} Of the genus Halosaurus which hitherto was known from a single example only, four species were discovered by the Challenger, showing that it is widely and abundantly represented in the deep sea.—(Günther, Zool. Chall. Exp., part 57, p. 232.)

^{page 367 note 6} Before the Challenger Expedition the known species of Macrurus were few in number … The dredge of the Challenger secured more than 140 examples referable to thirty species, and proved that this type of fishes is not only one of the most widely spread in the depths of all oceans, but also extremely abundant with regard to species and individuals.—(Günther, Zool. Chall. Exp., part 57, p. 122.)

^{page 367 note 7} Macrurus armatus has a wide range in the southern hemisphere, and is subject to some variation, the variation occurring in individuals from the same locality, and affecting the form of the head, length of dorsal spine, &c. The most striking deviation from the typical form is a kind of albino, not quite white, but of a much lighter colour than the ordinary specimens. In these albinos the scales are much thinner, the ridges sometimes scarcely visible, and if developed, they are merely keels without spines.—(Günther, Zool. Chall. Exp., part 57, p. 150.)

^{page 368 note 1} This species [Macrurus filicauda] is clearly one of those in this family which extend to the greatest depths. The decrease in the size of the eye, the very soft bones, the concomitant want of firmness in the structure of the scales, and the tail, which tapers into a very fine filament, indicate its abyssal abode. The scales are nearly all gone in all the specimens obtained. This species appears to be abundant in individuals, and has, like a true deep-sea fish, a wide distribution.—(Günther, Zool. Chall. Exp., part 57, p. 142.)

^{page 368 note 2} The formation of the head, the black colour of the body, together with the circumstances attending the capture of the three specimens first known, clearly indicate that the fishes of this genus [Melamphaës] are inhabitants of the depths of the ocean.. Lowe's two specimens were picked up at the surface, near Madeira, evidently in an exhausted condition; whilst the specimen described by Lutken was found in the stomach of a dolphin. The discoveries by the Challenger, and by the U.S.S. “Albatross,” have proved the surmise of the bathybial nature of these fishes to be correct.—(Günther, Zool. Chall. Exp., part 57, p. 26.)

^{page 368 note 3} The numerous species which I refer to this genus [Scopelus] are, as far as we know of their habits, nocturnal pelagic surface fishes, which are frequently caught at night in the surface net, but disappear during the daytime, when they evidently descend to a depth to which only a moderate amount of light penetrates. A few undoubtedly belong to the bathybial fauna, but with regard to the other species, I consider it equally probable that they accidentally entered the dredge during its ascent. Only a few specimens were captured in this manner, much fewer than of Argyropelecus, a fact which is no doubt due to their greater activity, by which they are enabled to make their escape on perceiving the approach of the net—(Günther, Zool. Chall. Exp., part 57, pp. 195–6.)

^{page 369 note 1} Wyville Thomson says this species was taken at, at least, six or seven Stations in the Atlantic and Southern Sea, but it is recorded in the Challenger Report only from two of these Stations.

^{page 378 note 1} Viz., Corallimorphus rigidus, Bathyactis symmetrica, Leptopenus discus, Atolla wyvillei, Pararchaster pedicifer, Ophiacantha cosmica, Ophiocten hastatum, Ophioglypha lacazei, Cystechinus vesica and wyvillii, Pourtalesia carinata and ceratopyga, Urechinus naresianus, Benthodytes sordida, Latmogone wyville-thomsoni, Oneirophanta mutabilis, Pseudostichopus villosus, Psychropotes longicauda, Scotoplanes globosa, Hyalinxcia benthaliana, Lætmonice producta, Nothria abranchiata ( = abyssicola), Cytliere acanthoderma and dasyderma and dictyon, Cytheropteron mucronalatum, Krithe producta, Serolis bromleyana, Nebaliopsis typica, Bentheuphausia amblyops, Hymenodora mollicutis, Nematocarcinus prozimatus, Munidopsis antonii and subsquamosa, Pagurodes inarmatus, Golossendeis gigas and leptorhynchus, Amussium meridionale, Silenia sarsii, Cirroteuthis magna, Eledone rotunda, Bugula reticulata, Salicornaria magnifica, Terebratula, wyvillii, Corynascidia suhmi, Cyema atrum, Gonostoma microdon, and Macrurus filicauda.

^{page 379 note 1} The most remarkable feature about Cladorhim inversa concerns its external form; compared with other “Crinorhiza1” forms it appears to be upside down; nor can we be certain that the surface which we have called “lower” in the description is not really the upper, and vice versa.—(Ridley and Dendy, Zool. Chall. Exp., part 59, p. 94.)

^{page 379 note 2} Esperella biserialis forms a most interesting and important link between the two genera Esperella and Cladorhiza, especially as regards external form. It is also particularly interesting in that it exhibits a distinctly bilateral symmetry.—(Ridley and Dendy, Zool. Chall. Exp., part 59, p. 76.)

^{page 379 note 3} We have thought it desirable in the case of the genus Phakellia to make use of external form as a generic character, otherwise we know of no character which would serve to separate the genus Phakellia from the genus Axinella.—(Ridley and Dendy, Zool. Chall. Exp., part 59, p. 170.)

^{page 379 note 4} Phakellia ventilabrum is typically an inhabitant of deep water, being common in depths over 100 fathoms, seldom occurring in shallower water, and going down to 1035 fathoms, as shown by the Challenger dredgings.—(Ridley and Dendy, Zool. Chall. Exp., part 59, p. 171.)

^{page 379 note 5} The range of external form exhibited by the genus Tedania is shown by the Challenger dredgings to be a very remarkable one indeed; hitherto known only by more or less massive or digitate specimens, we have had to add to the genus two new species, T. infundibuliformis and T. actiniiformis, characterised by very specialised, though quite different, external forms; the former being funnel-shaped, and the latter “actiniiform” (like an Actinia) with oscular projections on the top and a definite zone of pores. The species of this genus are very difficult to separate satisfactorily from one another; future researches may, very probably, by the discovery of intermediate forms, render possible the union of some which are at present, described as distinct.—(Ridley and Dendy, Zool. Chall. Exp., part 59, pp. 50–51.)

^{page 379 note 6} Tedania actiniiformis is a very important and well-characterised species; it is distinguished from all previously known by its external form and the arrangement of the pores in a definite zone. Its stylote spicule is the largest in the genus. It affords a really splendid instance of the manner in which sponges, which are shapeless masses when occurring in shallow water, assume in abyssal depths (in this case 2160 fathoms) a definite, symmetrical external form this is its chief interest, for the species of the genus hitherto known, from comparatively shallow water, are, par excellence, amorphous sponges.—(Ridley and Dendy, Zool. Chall. Exp., part 59, p. 56.)

^{page 379 note 7} The original type of the genus Trichostemma is Trichostemma hemisphæricum, which occurs not rarely at Lofoten in a depth of 120 to 300 fathoms on soft clay bottom. The Challenger adds two new species, both from a very great depth and a bottom of ooze or mud. It is essentially a deep-sea genus, and affords another example of the manner in which deep-sea sponges commonly assume a definite, symmetrical external form. In this case, however, the object of the flattened form and the long radiating spicules is obvious, namely, as pointed out by Sars, to support the animal in the soft mud on which it lies; in our new species, Trichostemma sarsii, this arrangement is brought to a much greater degree of perfection than in the original type of the genus. The genus has a very wide geographical range, being found in deep water off the north of Scotland, coast of Norway, Arctic Sea, Gulf of St Lawrence, off the Azores, N.E. coast of Australia, and W. coast of South America.—(Ridley and Dendy, Zool. Chall. Exp., part 59, p. 217.)

^{page 380 note 1} The single specimen on which the species. Schizopatiies crassa is based is the finest example of the Schizopathinæ contained in the Challenger collection. The stem is 57 cm. long, gracefully but gently flexuose, with a peculiar flattened sickle-like base replacing the rounded horny disc by which the Antipathinæ are attached to stones and other objects. In this case the species is probably fixed by the base being embedded in the mud constituting the bottom deposit in the area in which it occurs. The specimen is 53 cm. high, and measures 53 cm. also across the lower branches. The stem is simple, much flattened below, but gradually becoming cylindrical and slightly tapering above the lower branches.—(Brook, Zool. Chall. Exp., part 80, p. 147.)

^{page 380 note 2} Aulorchis paradoxa is a form of great interest as enlarging by a new genus and species the group of forms devoid of tentacles. Unluckily, I have had but the one solitary specimen for study, and even this was badly preserved, and had apparently suffered much from the dredge. … From my description it may be recognised that Aulorchis is one of the most interesting Actiniæ, and that it would be very desirable that a richer material of it should be acquired by fresh deep-sea investigations.—(Hertwig, Zool. Chall. Exp., part 71, pp. 21, 24.)

^{page 380 note 3} Paractis excavata is one of the most characteristic forms of the Challenger material, both as to the shape of the body, and as to its finer structure.—(Hertwig, Zool. Chall. Exp., part 15, p. 41.)

^{page 380 note 4} The small Actinia without tentacles, which I call Polyopis striata, was probably sac-shaped during life; its rounded posterior end probably stuck in the mud, whilst its broad anterior end formed by the oral disk projected freely.—(Hertwig, Zool. Chall. Exp., part 15, p. 101.)

^{page 380 note 5} In Polystomidium patens the tentacles have undergone retrograde formation to an extent which has hitherto been observed only in the genus Polyopis; the only traces of them are the terminal openings, which lead directly into the radial chambers and are surrounded by swollen margins, the remains of the tentacle wall. In their habit of body, in the endodermal position of the circular muscle, and in the presence of the marginal spherules, these animals are allied to the Antheadæ.— (Hertwig, Zool. Chall. Exp., part 15, p. 67.)

^{page 381 note 1} I have little to add to the very full accounts of the many varieties of Deltocyathus italicus contained in the memoirs cited. … It is very remarkable that none of the specimens obtained by us were attached, and that only one shows any trace of ever having been attached. This one specimen [from Station 285, South Pacific, 2375 fathoms], however, is large, and though somewhat imperfect, has a most distinct pedicle and scar of attachment, and evidently remained fixed up to a period of full maturity.—(Moseley, Zool. Chall. Exp., part 7, pp. 145, 146.)

^{page 381 note 2} Solenosmilia variabilis is a very widely-spread and characteristic deep-sea form, and varies exceedingly. Many specimens dredged by us were dead, old, and much broken, but always recognisable by the peculiar mode of branching and the texture of the ccenenchym.—(Moseley, Zool. Chall. Exp., part 7, p. 181.)

^{page 381 note 3} Of the stalked Crinoids Rhizocrinus has the farthest northern range (68° N.), but it has not been met with more than once (Station 122), or possibly twice (Station 323), south of the equator, and is limited to the Atlantic and Caribbean Ocean.—(Carpenter, Zool. Chall. Exp., part 32, p. 136.)

^{page 381 note 4} The form of the calyx in this species [Rhizocrinus lofotensis] varies very considerably; for it is nearly hemispherical in some specimens and much elongated in others. These last have the best developed arms; and to some extent, therefore, the forms with a low and wide cup must be regarded as premature. But differences of development will not entirely account for the variation, as the calyx of a young specimen found by Sars is distinctly higher (longer) than broad.—(Carpenter, Zool. Chall. Exp., part 32, p. 261.)

^{page 381 note 5} Of Dytaster exilis and its two varieties, carinata and gracilis, Sladen writes:—The variety carinata resembles the type more nearly than the variety gracilis does. The wide separation of the geographical positions of the type and its two varieties is of the greatest interest, and bears evidence to the enormous range of the Dytaster exilis form, and of the comparatively small amount of variation exhibited by this type in what may well be spoken of as extreme limits of position. The type comes from the Pacific, off the western coast of South America, the nearly allied variety carinata from the North Atlantic, off the eastern coast of the United States of America, whilst the more divergent variety—if, indeed, it be not a distinct species—was dredged in the South Atlantic, westward of Tristan da Cunha.—(Zool. Chall.Exp., part 51, p. 70.)

^{page 382 note 1} This remarkable and abnormal type of Asterid [Pythonaster murrayi] is altogether unlike any other form. Its general morphological structure appears to me to justify its inclusion in the family Pterasteridæ. Its aberrant peculiarities, however, necessitate in my opinion its separation in a distinct sub-family.—(Sladen, Zool. Chall. Exp., part 51, p. 531.)

^{page 382 note 2} Ophioglypha meridionalis is the southern cousin of Ophioglypha robusla, from which it differs in shorter arm spines, more swollen disk scales, smaller mouth papillæ, and fewer tentacle scales.—(Lyman, Zool. Chall. Exp., part 14, p. 41.)

^{page 382 note 3} The specimens [of Ophiomusium lymani] from the widely separated stations showed certain minor differences. For example, those from Station 235 [Japan] had more arm spines and rather more numerous lower disk plates, and the tentacle scales were entire, instead of divided. I have deemed it best to keep the varieties together, for the present.—(Lyman, Zool. Chall. Exp., part 14, p. 90.)

^{page 382 note 4} This singular genus [Ophiomyces] stands quite by itself, unless we compare its curious mouth papillæ with the spatula-like tentacle scales of Ophiopsila. All the specimens I have seen had a tendency to raise the arms above the disk, vertically; which shows that the muscular tension must have some peculiar proportion. … The peculiar twisting upward of the arms and disk of Ophiomyces is explained by the absence of radial shields, a want not yet observed in any other genus. It seems, then, that one function of radial shields is to keep the disk in shape, somewhat like the action of the sticks of an umbrella.—(Lyman, Zool. Chall. Exp., part 14, pp. 240, 242.)

^{page 383 note 1} At first glance Aceste bellidifera appears one of the most remarkable of Sea-urchins. … The enormous development of the sucker of the odd anterior ambulacrum is an eminently embryonic feature; it exists in the youngest stages of all the Spatangoids of which we know the development. … The general outline of the test as seen both in profile and from above is strikingly similar to that of the Schizasteridæ. In fact, this genus is of the greatest interest, showing as it does striking affinities on the one side to the Schizasteridæ and other Spatangina, such as Brissopsis, and on the other to the Pourtalesiæ, not only in the structure of its ambulacral system, but also from the position and shape of the actinostome, and the more or less cylindrical test modified in its outline from its Schizasterid affinities.—(Agassiz, Zool. Chall. Exp., part 9, pp. 195–6.)

^{page 383 note 2} Aspidodiadema is a most interesting genus, intermediate between the Cidaridæ proper and the Diadematidæ. It has like the latter a thin test, with long hollow primary spines nearly straight, and strongly verticillate, especially in the young. … The most remarkable feature of this genus is the structure of the ambulacral system.—(Agassiz, Zool. Chall. Exp., part 9, pp. 64–5.)

^{page 383 note 3} The test of this species [Cystechinus clypeatus] is quite stout, judging from the thickness of the fragments preserved. In the specimens from the greatest depths at which this species has been found, the test is much thinner than in the fragments which are found near the 1000 fathom line. As a general rule among the Pourtalesiæ, the test of the different species having an extended bathymetrical range varies very materially in thickness, according to the depth at which the specimens were dredged, specimens of the same species from shallower regions having pretty generally a comparatively stouter test.—(Agassiz, Zool. Chall. Exp., part 9, pp. 149–150.)

^{page 383 note 4} Phormosoma hoplacantha the largest Sea-urchin with which I am acquainted. It measures no less than 312 mm. in diameter, and when fully expanded, must have been a striking object. This species is remarkable for the large size of the primary tubercles, arranged both on the actinal and abactinal surface of the interambulacral areas in horizontal rows; on the abactinal surface they are distant, separated by large secondaries and miliaries, irregularly arranged on the coronal plates. … In alcohol the colour of the specimens of this species is dark violet, almost black both for the test and spines, and this formed a marked contrast to the white tips of the spines on the actinal surface. The existence of primary spines tipped with hoofs as in the Arbaciadæ is an interesting structural feature, connecting groups which thus far seemed somewhat isolated in their relationship to other Echinids. Thomson speaks of the wear of the base of the cones as if they had been in use for “vigorous locomotion” over the ground, as we know to be the case in one of the species of Arbacia of the eastern North American coast. In the Echinothuridæ the conical tip does not extend along the sides of the extremity of the spine, forming, as in the Arbaciadrc, a kind of cap; it is merely attached by a nearly horizontal base to the more flattened end of the spine. In consequence of this mode of attachment the tip is frequently lost.—(Agassiz, Zool. Chall. Exp., part 9, pp. 101–2.)

^{page 384 note 1} Since Fritz Müller's specimen [of Phascolosoma catharinœ] was labelled “Desterro,” one may infer that it was not obtained in trawling, but was found on the shore during ebb tide. The specimen of the Challenger Expedition, on the other hand, was obtained from a very considerable depth. This difference of distribution is not, however, by any means unique, for other true Sipunculids exhibit a similar occurrence on the shore and at considerable depths.—(Selenka, Zool. Chall. Exp., part 36, p. 13.)

^{page 384 note 2} An eyeless variety [of Eunoa opalina, Magellan Strait, Station 311, 245 fathoms] was trawled at Station 299, 2160 fathoms [S.E. Pacific]. It is of good size. The head is devoid of any trace of eyes, so that it forms another example of the influence of habitat on these important organs.—(M'Intosh, Zool. Chall. Exp., part 34, pp. 71–2.)

^{page 385 note 1} The genus Pseudocythere is widely distributed, occurring in the European seas as well as in distant regions of the southern hemisphere. As a fossil it has been recognised only in the Post-Tertiary deposits of the British Islands.—(G. S. Brady, Zool. Chall. Exp., part 4, p. 144.)

^{page 385 note 2} The genus Xestoleberis is widely distributed, containing apparently a very large number of species, and occurring abundantly in the seas of all parts of the world. So far, however, as we know of it palffiontologically, it would seem to be a genus of comparatively recent development.—(Brady, Zool. Chall. Exp., part 4, p. 124.)

^{page 386 note 1} Scalpellum darwinii is the largest species of Scalpellum known. Only a single specimen of it was dredged during the cruise of the Challenger attached to a manganese nodule.—(Hoek, Zool. Chall. Exp., part 35, pp. 110–111.)

^{page 386 note 2} Of this splendid species [Scalpellum eximium] only a single specimen was dredged, attached to a piece of pumicestone.—(Hoek, Zool. Chall. Exp., part 35, p. 100.)

^{page 386 note 3} This beautiful species [Scalpellum velutinum] is represented by a single specimen. Provisionally there must be referred to the same species three smaller specimens, which were dredged near the southern point of Portugal; yet I am not quite sure that they belong really to the same species. … The two Stations from which this species was obtained are both in the Atlantic; the one (near Cape St Vincent) has about the same northern latitude as the other (north of Tristan da Cunha) has southern latitude.—(Hoek, Zool. Chall. Exp., part 35, pp. 96, 99.)

^{page 386 note 4} Verruca gibbosa is the largest and the most beautiful of the deep-sea species.—(Hoek, Zool. Chall. Exp., part 35, p. 134.)

^{page 386 note 5} The specific name [of Andania ahyssorum] refers to the great depth from which this little creature was obtained, but is principally designed to call attention to its close relationship with the northern species Andania abyssi.— (Stebbing, Zool. Chall. Exp., part 67, p. 742.)

^{page 386 note 6} The specific name [of Orchomene abyssorum] has been given in allusion to the great depth from which the species is reported to have come. The single specimen was mounted during the voyage. Had this species been taken within any reasonable distance of Orchomene musculosus, the resemblance is so great that one might have been tempted to disregard the points of difference as due to some other cause than difference of species. It might be an accident that has caused one to be reported from the surface, and the other from so great a depth as 1900 fathoms, but that the Stations at which the two species were obtained are separated by nearly half the circumference of the globe is a circumstance not open to any such explanation.—(Stebbing, Zool. Chall. Exp., part 67, pp. 678–9.)

^{page 386 note 7} The specific name [of Podocerus hoeki] is given in compliment to Dr P. P. C. Hoek, who in 1882 gave a brief description and some figures of a new species, Podocerus tuberculatus, among the Crustacea of the “Willem Barents” Expedition. This species was obtained in lat. 71° 23′ N., long. 49° 38′ E., and judging only from the preliminary description and the figures of the two gnathopods, third uropods, and telson, presents an extraordinary resemblance to the Challenger species. … Considering the enormous distance between the places of capture, I have not thought it right to identify the two forms. Had they belonged to a single species, of so wide a distribution, it is highly improbable that it would have escaped discovery for so long, and then suddenly have been discovered almost simultaneously at two enormously distant points.—(Stebbing, Zool. Chall. Exp., part 67, pp. 1140–1.)

The single specimen [of Podocerus tuberculatus] described by Dr Hoek was taken in 1879 in lat. 71° 23′ N., long. 49° 38′ E., from a depth of 67 fathoms. Other specimens were obtained on Sept. 6, 1881, in lat. 77° 7′ N., long. 49° 37′ E., from a depth of 170 fathoms. An examination of these has shown that the fingers of the gnathopods precisely agree in dentation with those of the specimen described in the Challenger Report under the name of Podocerus hoeki. That specimen was taken in the neighbourhood of New Zealand, July 8,1874, in lat. 40° 28′ S., long. 177° 43′ E., and was supposed to come from a depth of 1100 fathoms. But though its habitat is separated by so vast a distance from the Arctic localities, there does not seem to be a single feature which can be relied on for distinguishing it from the species to which Dr Hoek had earlier given a name.—(Stebbing, “The Amphipoda collected during the voyages of the Willem Barents in the Arctic Seas in the years 1880–1884,” Bijdragen tot de Dierkunde, Afl. 17, 1894, p. 45.)

^{page 387 note 1} Two specimens of a deep-sea Isopod, belonging apparently to the same species [Aeanthomunna proteus], are referred to this genus; they were dredged in 700 and 1100 fathoms respectively off New Zealand. The genus is remarkable for its dense spiny covering, a condition met with in other deep-sea and cold-water Isopoda. The specimens only differ from each other in colour; the larger specimen (from 1100 fathoms) is of a pale buff colour, the smaller of a rich brown.—(Beddard, Zool. Chall. Exp., part 48, pp. 47–8.)

^{page 387 note 2} Acanthephyra sica appears to be both abundant and widely distributed; it was taken by the Challenger at eleven Stations, more or less distant from one another,—in the Atlantic and Pacific Oceans, as far north as Japan, and as far south as New Zealand. Its bathymetrical range is also great, since it has been taken at a distance of from less than half a mile to about three miles from the surface of the ocean. It appears to be very prolific also, since some of the females that were captured carry a large number of small eggs.—(Spence Bate, Zool. Chall. Exp., part 52, p. 743).

^{page 387 note 3} This genus [Aristeus] consists mostly of deep-water species, which swim freely in the sea, and during the cruise of the Challenger were never captured in less than 255 fathoms of water. … Aristeus armatus was captured at seven different localities at depths ranging from 1400 to 2350 fathoms. … Running down the eastern coast of South America, in the month of September 1873, the Challenger must have passed through a great multitude of young animals of this genus, varying in size from 4 to 14 mm., all of which bore evidence of belonging to allied species. The specimens corresponded closely excepting in such features as may be dependent upon age.—(Spence Bate, Zool. Chall. Exp., part 52, p. 311.)

^{page 388 note 1} The species of this genus [Sergestes] mostly live within 100 fathoms of the surface, but there is every reason to believe that this one [Sergestes profundus] resides near the bottom.—(Spence Bate, Zool. Chall. Exp., part 52, p. 429.)

^{page 388 note 2} A certain amount of variation is noticeable in specimens [of Parapagurus abyssorum] from different localities, more especially as regards the amount of pubescence and granulation on the chelipedes and ambulatory limbs. In a specimen from Station 133 [South Atlantic], the ophthalmic scales are bidentate, and the external prolongation of the second antennal peduncular joint is dentate. In spite of these apparent incongruities, an examination of the numerous specimens taken by the Challenger has convinced me that they all belong to a single species. … Parapagurus abyssorum is of special interest on account of its very extended distribution and deep-water habitat. It was taken by the Challenger in all the great ocean beds explored (with the exception of the Southern Ocean between the Cape and Australia), and nowhere in less than 1000 fathoms of water. [This species is recorded from Magellan Strait, 45 fathoms, but Henderson maintains that this is an error; he says that a shallow-water habitat for the species is quite out of the question.] It appears to be invariably associated with an Anemone which exerts a solvent action on the Gastropod shell originally selected as a dwelling-place by the Hermit; in many cases the shell has entirely disappeared, and in others it is greatly reduced, while the Anemone forms a soft and saccular covering on the exterior.—(Henderson, Zool. Chall. Exp., part 69, p. 88.)

^{page 388 note 3} The single specimen [of Tylaspis anomala] came from the greatest depth at which any Anomurous Crustacean was taken by the Challenger. The form of the abdomen points to the species having occupied some other dwelling-place than the Gastropod shell usually selected by the soft-tailed Pagurids.—(Henderson, Zool. Chall. Exp., part 69, p. 81.)

^{page 388 note 4} This true deep-sea species [Colossendeis brevipes] was dredged from the greatest depth at which a Pycnogonid has been found, viz., 2650 fathoms.—(Hoek, Zool. Chall. Exp., part 10, p. 72.)

^{page 388 note 5} I believe this species [Nymphon longicoxa] with its rudimentary eyes to form the transition from the shallow-water species to the true deep-sea species. … Nymphon longicoxa and Nymphon compactum were obtained [at the same Station] from a depth of 1100 fathoms. N. longicoxa shows rudimentary eyes, those of N. compactum are quite obsolete. N. longicoxa is one of the most slender, N. compactum one of the stoutest species dredged by the Challenger. In the one the auxiliary claws are wanting, whereas small ones are present in N. longicoxa, and in every other respect they are as widely different as two species of the same genus of Pycnogonids can be.—(Hoek, Zool. Chall. Exp., part 10, pp. 39, 42).

^{page 389 note 1} [Bugula margaritifera is] a very interesting form as coming from such an extreme depth. Its structure, as in most of the abyssal forms, is very delicate and transparent, and it is rooted by an infinite number of radical fibres, each attached to a dead Globigerina shell or similar small particle.—(Busk, Zool. Chall. Exp., part 30, p. 42.)

^{page 390 note 1} Bathysaurus agassizii, Goode and Bean, obtained at a depth of 647 fathoms in the Atlantic, lat. 33° 35′ N. long. 76° 0′ W., is probably not specifically distinct from the Pacific specimen [Bathysaurus ferox from Station 168, near New Zealand, 1100 fathoms]. It seems to be a fish with a somewhat deeper body, but, then, it was ascertained to be a “female, full of nearly mature eggs.”—(Gunther, Zool. Chall. Exp., part 57, p. 183.)

^{page 390 note 2} Ever since the discovery of this fish [lpnops murrayi] much uncertainty has prevailed with regard to the nature and function of the extraordinary apparatus on the upper side of the head; but from Professor Moseley's examination it seems to be almost beyond doubt, that it is a special form of phosphorescent organ. The power of producing light, and thereby attracting other creatures, mu9t be of great use to a fish, which, deprived of organs of sight and touch, would be unable to procure its food. The question of the homology of the luminous organ and its covering lamellse is still obscure; and no other specimen can be sacrificed to investigate the osteology of the skull. If, as Professor Moseley's investigations seem to prove, the luminous organ is not a modification of the eye, as Mr Murray and myself supposed at first, and if the organ of vision with the optic nerve has disappeared, the luminous organ is probably the homologue of that which is found in some Scopelids between the eye and nostril, and the covering plates would be the homologues of the præorbital membrane bones. With the abortion of the eyes the luminous organs with their praorbitals would have moved from their usual lateral position to the top of the head.—(Gunther, Zool. Chall. Exp., part 57, pp. 190–1.)

^{page 391 note 1} Not including the 48 species also occurring in the deep-water area of the Kerguelen Region (see footnote, p. 36).

^{page 392 note 1} Not including the 48 species occurring also in the deep-water area of the Kerguelen Region (see footnote, p. 36).

^{page 397 note 1} Not including the 48 species also occurring in the deep-water area of the Kerguelen Region (see footnote, p. 36).

^{page 403 note 1} Esperiopsis symmetrica is a very remarkable sponge, the most noticeable feature in which is the radiately symmetrical arrangement of the skeleton.—(Ridley and Dendy, Zool. Chall. Exp., part 59, p. 78.)

^{page 403 note 2} Gellius carduus is readily distinguished by its very characteristic external form, the surface resembling that of a large thistle-leaf, whence the specific name. The shape of the skeleton spicules is also very characteristic. … The variety magellanica is a very interesting geographical variety from the Strait of Magellan. The main features in which it differs from the type specimens concern the oxeote spicules which, in the variety in question, are much more pointed and a good deal shorter than in the type.—(Ridley and Dendy, Zool. Chall. Exp., part 59, pp. 39, 40.)

^{page 403 note 3} Three specimens of this interesting species [Iophon chelifer] are present; two are fairly large, but broken into fragments, the other is small, and occurs encrusting a branched Polyzoon. The latter is in all probability a young form, and differs in several minor respects from the larger specimens. … The species differs very decidedly from all described forms in the large size and also in the degree of elaboration of the bipocillate spicules. The other spicules are also larger in almost every case than the corresponding forms in other species of Iophon; Iophon (Alebion) piceum, Vosmaer, from Barents Sea, approaches it the most nearly in this respect.—(Ridley and Dendy, Zool. Chall. Exp., part 59, pp. 119–120.)

^{page 403 note 4} Only one specimen, broken into fragments, of this interesting species [Iophon laminalis] was obtained. In the fine state of development of its bipocillate microsclera it approaches Iophon chelifer, a specimen of which was obtained at the same Station; while in external form it probably comes near Iophon piceum, Vosmaer, from Barents Sea. The species to which it is perhaps most nearly related is, however, Iophon cylindricus (from off Cape Howe), which, like it, has the stylote spicule smooth.—(Ridley and Dendy, Zool. Chall. Exp., part 59, p. 121.)

^{page 404 note 1} The species which we have called Myxilla nobilis, and its varieties, have given us a great deal of trouble in determining their true relations; they appear to be sufficiently connected inter se to warrant us in considering them all as varieties of one species, and that species perhaps finds its nearest already known ally in Bowerbank's Hymeniacidon (Myxilla) paupertas [British]; the two species seem, however, to be distinct.—(Ridley and Dendy, Zool. Chall. Exp., part 59, p. 143.)

^{page 404 note 2} Phakellia papyracea is a very delicate species, which perhaps comes near to Bowerbank's Isodictya infundibuliformis [British], more especially if it should ultimately prove to be cup-shaped when perfect, but it is distinguished at once and absolutely from that species by the absence of the oxeote spicules, so that further comparisons are needless. In the absence of the oxeote spicules, however, it agrees with von Marenzeller's Crihrochalina ambigua [from Jan Mayen], but differs widely in the size of the spicules, while there do not seem to be two distinct sizes as in our sponge.—(Ridley and Dendy, Zool. Chall. Exp., part 59, p. 172.)

^{page 404 note 3} The most remarkable features of this sponge [Suberites mollis] are its great softness and looseness of texture, as compared with the more typical species of Suberites, and the reduction of the “dermal crust” of spicules, which no longer forms a distinct cortical layer.—(Ridley and Dendy, Zool. Chall. Exp., part 59, p. 205.)

^{page 404 note 4} Thouarella variabilis, of which there are numerous examples, varies to an extraordinary degree in the size of the calyces, the development of the spines, and the development of the colony, without it being possible thereby to sharply separate the individual forms specifically. Nevertheless one can generally distinguish the following three varieties from each other: a. the type (Station 145, 310 fathoms), b. var. brevispinosa (Station 145, 310 fathoms), c. var. gracilis (Station 150, 150 fathoms).—(Wright and Studer, Zool. Chall. Exp., part 64, p. 68.)

^{page 405 note 1} This form [Leptoptychaster antarcticus] is unquestionably the southern representative of Leptoptychaster arcticus (Sars) of the North Atlantic, to which it is structurally nearly related. … It is interesting to note that Leptoptychaster antarcticus is more nearly related to the distant Arctic form than to the comparatively neighbouring species Leptoptychaster kerguelenensis; perhaps a more extended series of specimens than we possess at present might lead to Leptoptychaster antarcticus being ranked as a variety only of the northern form. At present I do not feel justified in taking that step.—(Sladen, Zool. Chall. Exp., part 51, p. 192.)

^{page 406 note 1} Lithodes murrayi is apparently most closely allied to Lithodes maia [from the North Atlantic], but the latter species is of large size, and the spines on the carapace are more numerous and more uniformly equal in size.—(Henderson, Zool. Chall. Exp., part 69, p. 44.)

^{page 406 note 2} Neœra fragilissima is a large and very fragile species, in many respects similar to Neœra curia, Jeffreys [from the North Atlantic].—(Smith, Zool. Chall. Exp., part 35, p. 54.)

^{page 406 note 3} After careful study I have found it impossible to separate the southern form from the species of Linné [Puncturella noachina—n northern species].—(Watson, Zool. Chall. Exp., part 42, p. 43.)

^{page 407 note 1} The species taken by Ross' Antarctic Expedition (Tetilla antarctica) is not included in these and succeeding remarks.

^{page 412 note 1} Vosmaer (Sponges of the “Willem Barents” Expedition, 1881–2) has founded a genus Artemisina of which the most characteristic spicule is a toxite with spined ends like that which occurs in Amphilectus apollinis. Possibly the two species Artemisina suheritoides, Vosimaer, and Amphilectus apollinis, nobis, come near to one another and may even belong to the same genus, but they differ very widely in the texture of the sponge, and our present species possesses an additional form of megasclera not present in Artemisina.—(Ridley and Dendy, Zool. Chall. Exp., part 59, p. 124.)

^{page 412 note 2} This species [Amphilectus pilosus] is very well marked, and may be readily recognised both by its external appearance and its spiculation. All the spicules, except the minute isochela, which is unusually small, are of exceptionally large size. The toxa are probably the largest known examples of their kind. Some of them were found still enveloped by the mother-cell. The most interesting feature of the species is, however, the manner in which the toxa appear to develop into oxea.—(Ridley and Dendy, Zool. Chall. Exp., part 59, p. 127.)

^{page 412 note 3} Axinella balfourensis seems to be a very aberrant species of the genus, as indicated both by its external form and by the extreme sparseness of the skeleton.—(Ridley and Dendy, Zool. Chall. Exp., part 59, p. 180.)

^{page 412 note 4} Axinella mariana is a pretty little species, distinguished by its external form and by the peculiar shape of the smaller stylote spicule, which seems to be homologous with the “vermicular” spicule of Axinella crecta,&c.—(Ridley and Dendy, Zool. Chall. Exp., part 59, p. 180.)

^{page 412 note 5} We were at first inclined to regard this sponge [Desmacidon (Homœodictya) kerguelenensis] as a variety of the British species, Desmacidon (Homœodictya) palmata, which it very nearly approaches both in external form and in spiculation. There can be no doubt that the two are closely related, but on the whole it appears better to separate the Kerguelen form as distinct.—(Ridley and Dendy, Zool. Chall. Exp., part 59, p. 110.)

^{page 412 note 6} Vosmaer mentions under “Gellius vagabundus (O.S),” in the Sponges of the “Willem Barents” Expedition, a variety of that species possessing oxea and sigmata, similar in form to those of our species. His specimen, though containing a few styli, is obviously a true Gellius (Gellius vagabundus being Desmacella for us), and it is not improbably referable to Gellius flagellifer. It was obtained by the “Willem Barents” Expedition of 1880, and hence probably in the Arctic Sea, though the exact locality is unknown. Having regard to the want of definite characters in this species other than the form of the sigmata, we cannot further insist on the strong resemblance which this form bears to our species, as its locality is so far removed from that of Gellius flagellifer.—(Ridley and Dendy, Zool. Chall. Exp., part 59, p. 43.)

^{page 413 note 1} As regards external form it will be seen that Latrunculia bocagei is almost indistinguishable from the Kerguelen specimen of Latrunculia apicalis, and correspondingly different from Latrunculia brevis [Station 320, off the Rio de la Plata, 600 fathoms]; but in this case we are not inclined to set much value on external form as a specific character, for we have already seen that the specimens of Latrunculia apicalis from Kerguelen and from Station 320 respectively, differ in external appearance; indeed, to judge from the Challenger series of specimens of the genus, it would seem that external appearance depends on the locality, and that all the species from the same locality tend to have a similar external form.—(Ridley and Dendy, Zool. Chall. Exp., part 59, p. 239.)

^{page 413 note 2} Pachychalina (?) pedunculata resembles in several respects Vosmaer's Pachychalina caulifera (from the Arctic Sea), but it is cylindrical instead of flattened, and the shape of the spicules is different, being slender instead of broadly fusiform. The fibres in Pachychalina caulifera appear to contain a good deal more spongin than in the present species; indeed, it is only doubtfully that we include the latter in the genus at all; it forms another connecting link between the Renierinæ and Chalininæ, and shows how little value can be placed upon the amount of spongin present for purposes of classification.—(Ridley and Dendy, Zool. Chall. Exp., part 59, p. 25.)

^{page 413 note 3} No doubt the Kerguelen specimen [of Petrosia similis] forms a connecting link, but we think it advisable to distinguish between two closely allied species, Petrosia subtriangularis and Petrosia similis, the former characteristic of West Indian seas, and the latter of the seas south of the Cape. Two well-marked varieties of the latter are described below [one from near the Falklands, the other from the Philippines].—(Ridley and Dendy, Zool. Chall. Exp., part 59, p. 11.)

^{page 413 note 4} The single specimen [of Suberites caminatus] in the collection is attached by a broad base to an empty Brachiopod shell, and terminates in a singular oscular projection at the apex. … This is a very pretty and interesting little sponge; it may be recognised by its external form, and more especially by the projecting, well-marked osculum. … We have from Station 320 an interesting series of specimens which should perhaps be considered as belonging to a slight variety of the above species; they do not, however, appear to be distinct enough from the type to justify us in giving a varietal name. They occur, for the most part, encrusting dead branches of a Sporadopora, on which they form colonies, the different cushion-like individuals being united together by their bases. † The sponge is further remarkable as forming colonies by continuous gemmation, in a manner very rare in silicious sponges.—(Ridley and Dendy, Zool. Chall. Exp., part 59, pp. 198–9.)

^{page 413 note 5} Over sixty specimens of this remarkable sponge [Cinachyra barbata] were dredged off the shores of Kerguelen. They vary considerably in shape; the smallest is a prolate ellipsoid, the next a little larger is egg-shaped, both are provided with the characteristic oscules of the species, but without anchoring filaments; these are present, however, in specimens but very slightly larger, and by the time the sponge has attained a length of 20 mm., they are already matted together into a compact basal lump.—(Sollas, Zool. Chall. Exp., part 63, pp. 24–5.)

^{page 415 note 1} Antedon exigua, which represents Antedon tenella [of northern seas] in the Southern Sea, differs from it in the shortness of the later cirrus-joints and in the characters of the lower pinnules.—(Carpenter, Zool. Chall. Exp., part 60, p. 179.)

^{page 416 note 1} With the exception of two Atlantic species, Pteraster caribbœus [from the West Indian area] and Pteraster sordidus [from the “Talisman” or “Travailleur” dredgings], all the members of this genus are confined to the colder temperate and frigid zones. Notwithstanding its wide range of distribution the genus appears to show only a comparatively small amount of morphological plasticity.—(Sladen, Zool. Chall. Exp., part 51, p. 470.)

^{page 416 note 2} Solaster subarcuatus is nearly allied to Solaster endeca [from the Arctic and North Atlantic], of which it is perhaps the southern representative.—(Sladen, Zool. Chall. Exp., part 51, p. 457.)

^{page 416 note 3} Ophiacantha mago represents in the Antarctic zone the Arctic Ophiacantha anomala, from which it differs in having a minute slender tentacle scale and only five arms.—(Lyman, Zool. Chall. Exp., part 14, p. 187.)

^{page 416 note 4} Several species inhabiting the seas of the North bear a superficial resemblance to this form [Ophioglypha brevispina]:—such are O. albida, Forbes, O. robusta, Ayres, and O. nodosa, Lütken. And besides these O. Lymani, Ljungman, from Patagonia, is very like it.—(Smith, E. A., Phil. Trans., vol. 168, p. 281Google Scholar.)

^{page 416 note 5} In colour and general appearance it [Ophioglypha hexactis] approaches O. sarsii, Lütken, of the Greenland coast, which seems to be its nearest ally; but these species are so different from one another in detail, that it is needless to specify their distinctions.—(Smith, E. A., Phil. Trans., vol. 168, p. 280Google Scholar.)

^{page 416 note 6} The Challenger series [of Hemiaster cavernosus] is so extensive, and shows such a range of variation both in form and in the structure of the petals according to age and sex, that I am quite convinced it is impossible to define the Kerguelen specimens as a different species [Hemiaster conlatus], Dr Studer and Mr Smith enumerate it as a distinct species in their lists of Kerguelen Echinoderms. … From the evidence furnished by the large material collected by the Challenger, there seems but little doubt that species which have thus far been distinguished as Hemiastar auatralis, philippü, and cavernosus are all different stages of growth of one and the same species, but owing to the great difference in structure between the ambulacral petals of the males and females, and the extraordinary changes this species passes through from its youngest stage until it has reached its adult sexual form, it was very natural that these several stages of growth should on scanty material have been regarded as so many distinct species. The coloration of specimens from different localities appears also quite distinct, and in some cases the test and spines are of a light brownish-yellow, in striking contrast to the dark coloured specimens found at other localities.—(Agassiz, Zool. Chall. Exp., part 9, pp. 183–4.)

^{page 417 note 1} The examination of the vast harvest brought home by the Challenger Expedition from different regions of the world, from the shore as well as from the abysses of the ocean, shows clearly that those Holothurids which live in the deep sea have two different derivations. The great majority are Elasipoda, which cannot be derived from the present shallow-water fauna, but must have originated from a past type that certainly bore another stamp. On the other hand, so far as can be judged from the results of the expeditions hitherto made, the remaining Holothurids met with in the great depths are comparatively few, both in species and individuals, and unmistakably show the closest relation to the present shallow-water fauna; so that while the Elasipoda have retired toward the abysses an infinitely long time ago, the latter have emigrated only at a comparatively much later period. … With regard to the bathymetrica distribution of Apoda and Pedata, our present knowledge does not enable us to speak of any results of very general value. However, the Challenger Expedition has been successful even in these respects, several important discoveries having been made, proving that the present shallow-water fauna has far more outposts in the great depths of the ocean than at first supposed. Before the Challenger Expedition set out, only a very few forms belonging to the Apoda and Pedata were known from depths exceeding 100 fathoms, and scarcely one below 200 fathoms. This list [of the species met with in the deep sea at depths from 500 fathoms and under] induces me to believe the following remarks to be true, or, at least, to have some probability

1. Descendants of the recent shallow-water Holothurioidea have escaped to the greatest depths at which any living Holothurid has been obtained, viz., 2900 fathoms, but they are by no means so prevalent as the Elasipoda, nor do they form such a characteristic feature in the abyssal fauna.

2. Most of the forms met with in the deep sea below 500 fathoms are distinct from the shallow-water species though they belong to the same genera.

3. Several species have a vast bathymetrical distribution, some individuals of them still living near the shore, others having descended without any obvious change in their organisation into the considerable depth of 500 to 700 fathoms or exceptionally even deeper.

4. A wider distribution seawards of a species seems to take place preferably in the northern and southern oceans, where the different belts proceeding from the vicinity of land outwards would seem to have in general a greater uniformity in temperature and other physical conditions than in the tropical and subtropical regions, where it is stated that the belts below 100 or 200 fathoms have lost the influence of the climate, etc., and present conditions of life far different from those above them. Such forms are Myrotrochus rinkii from shore to 500 fathoms; Echinocucumis typica from about 40 to 530 fathoms; Thyone raphanus from 20 to 672 fathoms; Holothuria intestinalis from 10 to 650 fathoms; Holothuria tremula from 20 to 672 fathoms; Trochostoma violacea from 20 to 700 fathoms; Thyonidium pellucidum from about 30 to 1081 fathoms, etc. The two deep-sea species of Synapta are scarcely distinguishable from some of the shallow-water species.

5. Pœlopatides, Pseudostichopus, Acanthotrochus and probably even Ankyroderma are the only true deep-sea genera of Apoda and Pedata, no representatives of them having hitherto been obtained near the shore or, at least, from any trifling depth. Species of these genera very seldom seem to thrive at a less depth than 500 fathoms.

6. Among the Apoda the Synaptidæ are, with a very few exceptions, shore forms, living near the surface of the sea, while the Molpadidæ are probably in a state of emigration seawards, a great number of them having already reached the abysses and settled there.

7. The Dendrochirotse and Aspidochirotse are still true shore or shallow-water forms, though there are even here many exceptions, proving that their representatives are thriving even at great depths.—(Théel, Zool. Chall. Exp., part 39, pp. 1, 2, 6, 7.)

^{page 417 note 2} It is remarkable that the forms [of Chirodota purpurea] dredged at the Falkland Islands are devoid of any sigmoid deposits, while those found by the Challenger Expedition in the Strait of Magellan and at Kerguelen Island have, as a rule, such deposits. Therefore it seems to me far more credible that Holothuria purpurea of Lesson, which was also obtained at Falkland Islands (Soledad), is identical with the above described forms rather than with Studer's Sigmodota purpurea [re-named by Théel Chirodota studerii], which is found living in the Strait of Magellan and at Kerguelen Island. … The specimens [of Chirodota coyitorta] brought home from Station 314 [Falklands] differ from the others in having the aggregations of wheels much more crowded, while the aggregations of wheels, especially in the individuals obtained at Marion Island, are very scattered, so that they almost appear at first sight to be devoid of them. The specimens examined by me differ from Ludwig's type in their violet colour. It seems very peculiar that all the individuals dredged by the Challenger Expedition in several localities at the Kerguelen Islands, as well as in or in the neighbourhood of the Strait of Magellan, belong to Ludwig's Chirodota contorta. Not a single specimen of Studer's Sigmodota purpurea was obtained, therefore I cannot help thinking that the very scattered aggregations of wheels have escaped the attention of Studer, because of the sigmoid bodies being so conspicuous by their number as well as by their size.—(Théel, Zool. Chall. Exp., part 39, pp. 15–16)

^{page 419 note 1} Lumbriconereis kerguelensis evidently takes the place of the European Lumbriconereis nardonis, to which it is closely allied in the structure of the dental apparatus.—(M'Intosh, Zool. Chall. Exp., part 34, p. 247.)

^{page 419 note 2} This form [Nereis (Platynereis) eatoni] which was first procured by Bev. Mr Eaton, of the Transit of Venus Expedition, seems to take the place of Nereis dumerilii, Aud. and Ed., of the European seas, and indeed it is allied in a very close manner to the latter species.—(M'Intosh, Zool. Chall. Exp., part 34, p. 224.)

^{page 420 note 1} The general form of this species [Cythere foveolata] is very familiar; many might be named which approach it rather closely, but no described species seems to be absolutely identical with it. The nearest, perhaps, are Cythere borealis, Brady—an Arctic form,—and Cythere œdichilus, Brady, a fossil of the Antwerp Crag.—(Brady, Zool. Chall. Exp., part 4, p. 76.)

^{page 420 note 2} Seen on the dorsal surface, this species [Cythere kerguelenensis] bears a close resemblance to the common British Cythere albomaculata, Baird, but the shell is much more coarsely sculptured, while the spinous margins and very broadly reniform lateral outline are constant distinctive characters.—(Brady, Zool. Chall. Exp., part 4, p. 79.)

^{page 420 note 3} A few detached valves brought by the Challenger from off Prince Edward Island in the Southern Ocean are in no respect distinguishable from the fossil specimens described by me in a Monograph of the Fossil Ostracoda of the Antwerp Crag, under the name Cythere polytrema. It is extremely interesting to note the occurrence, alive in this distant region, of so well marked a European fossil.—(Brady, Zool. Chall. Exp., part 4, p. 87.)

^{page 420 note 4} Though bearing considerable resemblance to the northern species Cytheropteron latissimum (Norman), this [Cytheropteron assimile] is easily distinguished by the character of the surface-sculpture, which shows no tendency to run into transverse grooves; the lateral alee, too, are considerably more prominent.—(Brady, Zool. Chall. Exp., part 4, p. 139.)

^{page 420 note 5} Cytheropteron scaphoides is not unlike in general character to Cytheropteron subcircinatum, Sars, but is very much less tumid.—(Brady, Zool. Chall. Exp., part 4, p. 136.)

^{page 420 note 6} The nearest known ally [of Cytherura lilljcborgi] is probably Cytherura clathrata, Sars, with which it closely agrees in style of surface-sculpture though quite different in proportions and general contour.—(Brady, Zool. Chall. Exp., part 4, p. 133.)

^{page 421 note 1} Balanus hirsutus [taken by H.M.S. “Triton” in the Faroe Channel, 516 fathoms] and Balanus corolliformis [from Station 150, 150 fathoms] are two nearly related species, corresponding in all essential respects. I must consider them, however, as different species, because their shape is quite different, and in the second place, because the tergum shows very striking differences also. … Balanus corolliformis is a very remarkable species, and I confess to have been long in doubt whether it was a Balanus or not. The investigation of specimens of a nearly related form [Balanus hirsutus], which showed the same characteristic differences from the other species of the genus, convinced me that I was right in considering them as representatives of a new section of the genus Balanus.—(Hoek, Zool. Chall. Exp., part 25, pp. 155, 6, 8.)

^{page 421 note 2} To judge by the results obtained at Kerguelen Island in the Southern Ocean it is much rather in Antarctic than in Arctic waters that the explorer who devotes himself to the search after Amphipoda may hope to find new and surprising forms. There are, it is true, some remarkable instances in which the same species occurs both far north and far south, but these are after all not very numerous.—(T. K. R. Stebbing, “The Amphipoda collected during the voyages of the Willem Barents in the Arctic Seas in the years 1880–1884,” Bijdragen tot de Dierkunde, Afl. 17, p. 1, 1894.)

^{page 421 note 3} A specimen of Amphilochus from the Clyde, kindly sent me by Mr David Robertson, agrees in most respects with Boeck's description of his Amphilochus tenuimanus, and has also a great resemblance to the present species [Amphilochus marionis]; the maxillipeds in the Scotch form and in that from the Southern Ocean are remarkably alike, altogether the sum of the differences, added to the great distance between the localities at which the specimens ccur, makes it unsafe to place the northern and southern examples in one and the same species.—(Stebbing, Zool. Chall. Exp., part 67, p. 746.)

^{page 422 note 1} I cannot find any points of difference that would justify the separation of this southern species from the northern Eusirus longipes, Boeck.—(Stebbing, Zool. Chall. Exp., part 67, p. 969.)

^{page 422 note 2} Euthemisto thomsoni appears to stand extremely near to the northern Euthemisto bispinosa (Boeck).—(Stebbing, Zool. Chall. Exp., part 67, p. 1416.)

^{page 422 note 3} The specific name [of Liljehorgia consanguinea] refers to the obviously very close relationship between this southern species and the northern Liljeborgia pallida, Spence Bate.—(Stebbing, Zool. Chall. Exp., part 67, p. 984.)

^{page 422 note 4} Metopa nasutigenes is very like Metopa nasuta, Boeck [a northern species], which also has the large beak or nose formed by the first joint of the upper antennæ. Hence the specific name is a hybrid, to express “of the lineage of nasuta.”—(Stebbing, Zool. Chall. Exp., part 67, p. 756.)

^{page 422 note 5} In the course of the description the differences have been noticed between this [Orchomene cavimanus] and the very similar species, Orchomene musculosus, taken at an enormously distant Station to the south of Japan.—(Stebbing, Zool. Chall. Exp., part 67, p. 681.)

^{page 422 note 6} This species from the south [Pardalisca marionis] is remarkably like the northern species Pardalisca cuspidata.—(Stebbing, Zool. Chall. Exp., part 67, p. 999)

^{page 423 note 1} Speaking of Podocerus falcatus, Stebbing says: There is the possibility, as I have elsewhere suggested, that these creatures may have travelled out from our own waters along with the vessel to the southern latitudes at which they were captured.—(Zool. Chall. Exp., part 67, p. 1135.)

^{page 423 note 2} This species [Leptognathia ausiralis] is probably new, but agrees very closely with Leptognathia longiremis, Sars, from the Norwegian North Atlantic Expedition.—(Beddard, Zool. Chall. Exp., part 48, p. 127.)

^{page 423 note 3} Only five species of this genus [Munna] are at present known, all of which are inhabitants of the shallow water off the coasts of Great Britain, Norway, North America, &c.; in the present Eeport I have two new species to add, both of which are from shallow water off Kerguelen.—(Beddard, Zool. Chall. Exp., part 48, p. 24.)

^{page 423 note 4} Pleurogonium albidum and Pleurogonium serratum [from Kerguelen] evidently come very near to Sars' Pleurogonium rubicundum [from Norway].—(Beddard, Zool. Chall. Exp., part 48, p. 28.)

^{page 424 note 1} The Norwegian form Campylaspis verrucosa would seem to be nearly related to the present species [Campylaspis nodulosa], at least as regards the sculpture of the carapace.—(Sars, Zool. Chall. Exp., part 55, p. 68.)

^{page 424 note 2} In general appearance Diastylis horrida would seem to be most nearly related to the northern form Diastylis lucifera (Kröyer).—(Sars, Zool. Chall. Exp., part 55, p. 55.)

^{page 424 note 3} Leucon assimilis is very nearly allied to the northern species Leucon nasicus, Kröyer, from which it may, however, be distinguished by the somewhat different form of the pseudorostral projection.—(Sars, Zool. Chall. Exp., part 55, p. 34.)

^{page 424 note 4} Colossendeis megalonyx resembles Colossendeis proboscidea (Sabine) [from the Arctic] in the form of the proboscis. That species, however, is a great deal stouter, and has a much larger body with comparatively short legs.—(Hoek, Zool. Chall. Exp., part 10, p. 69.)

^{page 424 note 5} In some respects Nymphon brachyrhynchus shows a resemblance to Nymphon strœmii of Kröyer [from the Arctic and North Atlantic].—(Hoek, Zool. Chall. Exp., part 10, p. 48.)

^{page 425 note 1} This species [Nymphon brevicaudatum] is allied to the boreal N. brevitarse, Kröyer; but it is distinguished by its more robust form, its long and slender oculigerous tubercle, its longer tarsal joints, &c.—(Miers, E. J., Phil. Trans., vol. 168, p. 213Google Scholar.)

^{page 425 note 2} Cardita astartoides, as pointed out by Martens, bears a great resemblance to the North American Cardita borealis, and may be regarded as the southern representative of that form. It certainly i3 more like that species than Cardita velutina from South Patagonia, which we should not expect, considering how similar the fauna of that region and of Kerguelen Island appear to be.—(Smith, Zool. Chall. Exp., part 35, pp. 212, 213.)

^{page 425 note 3} Cryptodon marionensis is the southern form of Cryptodon gouldii, Philippi, and Cryptodon flexuosus, Montagu, both of which species it closely resembles.—(Smith, Zool. Chall. Exp., part 35, p. 194.)

^{page 425 note 4} Two specimens from Kerguelen I cannot distinguish from this well-known European species [Kellia suborbicularis], which has not, I believe, been previously met with farther south than the Canaries.—(Smith, Zool. Chall. Exp., part 35, p. 201.)

^{page 425 note 5} This polymorphous species [Saxicava arctica], judging from the shells alone, is apparently distributed all ove the globe. Of the animals inhabiting them we know nothing except those of northern varieties. The shells vary immensely in form, thickness, and ornamentation. Those found off the South African coast are especially remarkable for the great development of the spines on the posterior side, and have been raised to specific rank by Mr Sowerby under the name of Saxicava spinifera. Many localities have already been cited for this species, and among them may be mentioned Greenland, Norway, Great Britain, Sitka, Japan, California, Peru, Patagonia, Canaries, Madeira, Mogador, Mediterranean, Madagascar, Cape of Good Hope, Australia, New Zealand, &c.; and it is also found fossil in several Upper Tertiary formations.—(Smith, Zool. Chall. Exp., part 35, p. 78.)

^{page 426 note 1} Thracia meridionalis is the southern representative of the Greenlandic species Thracia truncata, and indeed differs so slightly from it that it is with considerable hesitation I venture to describe it as distinct, being mainly influenced to do so by the difference of locality.—(Smith, Zool. Chall. Exp., part 35, p. 69.)

^{page 426 note 2} The step from Madeira to lat. 46° S. is so enormous, that I was glad to have my identification of the specimen [of Homalogyra atomus] confirmed by one who knows the species so well as Dr Gwyn Jeffreys does. It is extremely abundant in Madeira, and careful search will probably supply very many additional localities for its dwelling.—(Watson, Zool. Chall. Exp., part 42, p. 121.)

^{page 426 note 3} Natica fartilis so closely approaches Natica affinis [a northern species] that I have hesitated very much to separate them, and have been glad to be strengthened in so doing by the opinion of Professor von Martens and Mr E. A. Smith.—(Watson, Zool. Chall. Exp., part 42, p. 447.)

^{page 427 note 1} Natica (Amauropsis) suturalis has so strongly the aspect of Natica islandica that I can easily believe connecting links will yet establish their identity. The age of Natica islandica and its distribution, as well as its present habitat in Subarctic and Arctic seas, make its presence in Antarctic regions more probable. But for the present it is impossible to unite them.—(Watson, Zool. Chall. Exp., part 42, p. 456.)

^{page 427 note 2} On comparing this [Natica (Lunatia) grönlandica from Heard Island] with Sars' specimens from Norway I am not quite satisfied, and yet I cannot part them. … It was unsatisfactory to put a Kerguelen shell to an Arctic species without fuller conviction, and I was glad, therefore, to have my determination of the species confirmed by Mr E. A. Smith.-—(Watson, Zool. Chall. Exp., part 42, p. 448.)

^{page 427 note 3} I give this species [Odostomia rissoides from Marion Island] on the authority of Dr Gwyn Jeffreys. I had remarked the shell's great resemblance in form to Odostomia rissoïdes, but the distinct and strong spiral structure which characterises it, coupled with the locality, prevented my referring it to that species.—(Watson, Zool. Chall. Exp., part 42, p. 481.)

^{page 428 note 1} I have described this [Trophon declinans] as a new species with very great reluctance. My own opinion is that it is a large thin variety of T. truncatus, Ström; and that opinion is shared by Mr E. A. Smith. Dr Gwyn Jeffreys, however, and Professor G. O. Sars decidedly hold it as distinct; and their extensive acquaintance with the large northern variety of T. truncatus makes their judgment of great weight.—(Watson, Zool. Chall. Exp., part 42, pp. 168–9.)

^{page 428 note 2} Turritella austrina is very like our British T. terebra, Linné, but is stumpier in form, smaller, with a much more impressed suture, and fewer spiral threads.—(Watson, Zool. Chall. Exp., part 42, p. 471.)

^{page 428 note 3} Bergh enumerates two species of Archidoris from the North Atlantic, one species from the North Pacific, and two new species from Kerguelen.—(Zool, Chall. Exp., part 26, p. 85.)

^{page 430 note 1} I unite under this species [Amaroucium variabile] a large number of specimens, collected in the neighbourhood of Kerguelen Island, which present great variations in form, size, colour, and some other particulars. They are, however, all closely related to one another, and although it might be possible to break them up into two or three species, I believe that the differences between the extreme forms are sufficiently bridged over by intermediate conditions to warrant one in regarding them as composing a single species only. They form an extremely interesting series on account of the way in which they illustrate individual variation.—(Herdman, Zool. Chall. Exp., part 37, p. 216.)

^{page 430 note 2} Ascidia challengeri is a large and somewhat variable species, which appears to be common at Kerguelen Island. In the first part of the Preliminary Report it was considered as being identical with Ascidia mentula, O. F. Müller, a species to which it is closely allied.—(Herdman, Zool. Chall. Exp., part 16, p. 203.)

^{page 431 note 1} The study of the Antarctic surface fish-fauna, and its comparison with that of the Arctic regions, is one of the most instructive portions of zoogeography. The abundance of fish-life appears to decrease in the same proportion towards both Poles. The forms peculiar to the Antarctic are analogous to those of the north; thus the Cottoids of the north are represented by the Nototheniæ, Chœnichthys, &c, of the south, the Salmonoids by the Haplochitonidæ; yet there is no such relation between the representative forms as might be considered to be genetic. The resemblance is rather an external one, indicated by the general form of the body, structure and development of the fins, presence of an adipose fin, &c. Besides those fishes which are peculiar to the Antarctic some other forms well developed in the north, but nearly or entirely disappearing between the tropics, reappear, as Sebastes, Agonus, Spinax, Myxine, differing but little from their northern congeners.—(Gunther, Zool. Chall. Exp., part 6, p. 14.)

^{page 431 note 2} It may be of interest to insert here some general remarks of Dr von Willemoes-Suhm on the results of the shallow-water dredgings and trawlings taken at Kerguelen by the Challenger in the month of January 1874, extracted from the Challenger Report, Summary of Results, pp. 478–480, as he refers to a few animals not included in our list, the specimens of which probably did not reach the hands of the specialists who described the Challenger collections:—“The prevailing animals in the shallow-water dredging on January 17 were Echinodermata, next to which Sponges and Polyzoa were represented by a considerable number of genera and species. There were also a large simple Ascidian and a small composite one; simple Ascidians were apparently far from numerous here, nor, indeed, were hey abundant at any place where we have dredged in shallow water,—an interesting fact, if confirmed as we go on. Annelids were represented especially by numerous Aphroditaceans, belonging probably to the genera Aphrodita and Hermione, and a few Terebellids; there were also two Nemerteans, one a particularly large one with immense mouth. The almost total absence of higher Crustacea in the shallow-water fauna of these Antarctic islands is very astonishing. Near Marion Island a caridid shrimp was taken in great numbers, while here at Kerguelen not a single Decapod was found. An Amphipod, the Gammarus which in water takes the place of flies on land, was very common. For Isopods this seemed to be a favourite territory, Serolis being probably the most numerous in specimens and species, though small Sphæroniidse were not uncommon, and several specimens of a spiny Arcturus were taken; most of these Isopods had eggs or young in their breeding pouches. A species of Tanais obtained to-day was very interesting on account of its method of reproduction; it had no breeding lamellæ, as in all Isopods hitherto known, but instead two sacs at the base of the fifth pair of legs, which contained the young ones, reminding one very much of the well-known sacs at the base of the last pair of feet in Copepods. They were in every way similar, but here rounded and not elongated, about 2½ inches in diameter, and containing each about twenty embryos, which evidently remain there, as they do in the breeding pouches of other species, until they Lave attained their full development. Among the Molluscs there was a large white Nudibranch and a few Gasteropoda and Lamellibranchiata, all indicating great uniformity in the Molluscan fauna of the place. On January 20, the dredge brought up some specimens of Siphonostomum, a genus very common in the north and in the Mediterranean, which has a great resemblance to the northern species. These worms have, besides two long tentacles, a quantity of branchial filaments and papillæ surrounding the mouth; at the first segment there are also very strong and long sette standing erect in front, and having a peculiar structure; in the skin are many glands that exude a slimy secretion, by which they are generally surrounded. On January 21, the dredge brought up large specimens of Serolis, and in the trawl were great quantities of a Caprella, the male of which is very much elongated, and has enormously long anterior claws; the female had eggs in its pouch. On January 29, the dredge brought up many Echinodernis, a singular round simple Ascidian, and among the worms Clymmia and Terebella, along with Dentalium and other Molluscs. The trawl procured in the afternoon a prodigious quantity of animals, including specimens of a large Rossella, a smaller siliceous Sponge, and a stalked one; small Planarians and Nemerteans; many Annelids, among which were large quantities of Aphrodita and Siphonostomum, and also a small Sipunculus; quantities of Polyzoa, also simple and composite Ascidians; among Crustacea, an Ostracode belonging to the Cypridinidæ, some of the big members of which seem to inhabit deeper water, many Pycnogonids, among which were a small Nymphon, a large red Nymphon, and Pycnogonum (several of these spiders were overgrown by an Alcyonium, which much enlarged their appearance), two female specimens of Nebalia, differing only slightly from the Mediterranean Nebalia geoffroyi, several male and female specimens of a Petalophthalmid, an inch long, apparently belonging to my genus Crozetia[=Amblyopst, Sars], established on a much larger species from deep water (these specimens with their larvæ show that the animals undergo the Mysis-development, and that the genus is more nearly allied to the ordinary Mysis than to the deep-sea Petalophthalmids); among the Isopods were quantities of Serolis, old and young in all stages of development, a few specimens of the Tanais taken on the 17th, and males and ovigerous females of Pranisa (Anceus), showing hardly any differences from the species studied by Dohrn at Plymouth and described by Spence Bate in his British Sessile-Eyed Crustacea; Amphipods were represented by several small species, and a large one distinguished by a bright-red process at the front of the carapace, containing, under a simple chitinous layer, pigment arranged in hexagons (I could discover no trace of bodies entitling them to be called eyes, of which they are very probably the rudiments); of Ciunacea a little Cuma was very abundant, in the males of which the second antenna seem to remain in the same state of development as in the female. Except the Schizopod already mentioned, not a single member of the higher stalk-eyed Crustacea was taken, and probably no others exist here in shallow water. Three specimens of a Raia, not mentioned in Giinther's Catalogue of Fishes, were also obtained.”

^{page 434 note 1} Nine of these species have subsequently been recorded from South Georgia, viz., Asterias meridionalis, Ophioglypha hexactis, Lagisca antarctica [ = Harmothoë vesiculosa]. Nereis kerguelensis, Nymphon brevicaudatum, Litorina [ = Pelilitorina] setosa, Hemiarthrum setulosum, Chorizocormus reticulatus, and Colella concreta; there are besides other eight species with a wider distribution (as will be noticed in the succeeding notes) recorded from South Georgia, viz., Porania antarctica, Hemiaster cavernosus, Serolis septemcarinata, Modiolarca trapezina, Hydrobia [ = Lœvilitorina] caliginosa, Trochus (Photinula) expansus, Colella pedunculata, and Harpagifer bispinis, making altogether seventeen species in our list found since at South Georgia (see Pfeffer, “Die Niedere Thierwelt des antarktischen Ufergebietes,” Ergebnisse der deutschen Polar-ExpedAtionen).

^{page 443 note 1} See “An account of the Petrological, Botanical, and Zoological Collections made in Kerguelen's Land and Rodriguez during the Transit of Venus Expeditions, carried out by order of Her Majesty's Government in the years 1874–75,” Philosophical Transactions, vol. 168 (extra volume), 1879Google Scholar; Kidder, J. H., “Contributions to the Natural History of Kerguelen Island, made in connection with the United States Transit-of-Venus Expedition, 1874–75,” Bull. U.S. Xat. Mus., No. 3, 1876Google Scholar; Studer, “Über Echinodermen aus dem antarktischen Meere, gesammelt auf der Eeise S.M.S. Gazelle um die Ercle,” Monutsber. d. k. Akad. d. Wiss. Berlin, 1876, pp. 452–463; Studer, Ibid., 1878, pp. 542–546, 633, 661; Studer, , “Die Fauna von Kerguelensland,” Archiv für Naturgeschichte, Jahrg. xlv. Bd. i. pp. 104–141, 1879Google Scholar; Studer, “Uebersicht iiber die Ophiuriden, welche, wahrend der Eeise S.M.S. Gazelle um die Erde 1874–1876 gesammelt wurden,” Abhandl. d. k. Akad. d. Wiss. Berlin, 1882, pp. 1–37; Studer, “Isopoden, gesammelt wahrend der Reise S.M.S. Gazelle um die Erde 1874–76,” Ibid., 1883, pp. 1–28; Grube, “Annelidenausbeute von S.M.S. Gazelle,” Monatsber. d. k. Akad. d. Wiss. Berlin, 1877, pp. 509–554; Crosse, , “Faune malacologique des lies Kerguelen,” Journ. de Conchyliologie, ser. 3, tom. xvii. p. 1, 1877Google Scholar.

^{page 443 note 2} Of the Sponges collected at Kerguelen by the British Transit of Venus Expedition, H. J. Carter writes:—The collection of Sponges from Kerguelen Island is very limited in extent. So far as it goes, it may be said to present a European, and more especially a British facies. Half of the species at the fewest, may be picked up at any time on the beach of South Devon:—viz., Isodictya rosea, Halichondria plumosa, H. carnosa, and H. sanguinea. To these we might add a fifth species, H. panicca, for the Kerguelen variety differs from the normal British form only in the possession of spicules twice the size of the latter. Of the three species remaining Thalysias is common to the Mediterranean and the seas between the Americas; the Ute occurs on the N.W. coast of Spain and in the Mediterranean; and one only, the Tethya, is decidedly antarctic. This last was the only specimen obtained from a considerable depth; all of the others were either collected with the grapple within the Laminarian zone, or were the produce of shore-collecting between tide-marks or amidst the refuse of the beach. Probably more extended research would have brought to light divers of the many peculiar forms which abound in the Cape seas and in those of the southern part of Australia. In the course of my examination I have met with very few Foraminifera, no Globigerina, and no coccoliths.—(Phil. Trans., vol. 168, p. 286.)

Carter refers some Sponges collected at Kerguelen by the British Transit of Venus Expedition to the species Thalysias subtriangularis, Duchassaing and Michelotti, and Tethya antarctica. Carter. Ridley and Dendy refer the first to their Petrosia similis, regarding it as distinct from the West Indian Petrosia subtriangublaris, while Sollas refers the second to his Tetilla grandis, regarding it as distinct from Tetilla antarctica obtained by Ross Antarctic Expedition in 206 and 300 fathoms in the neighbourhood of Victoria Land.

^{page 444 note 1} Pfeffer records the widely distributed species, Sertularia operculata, Linné, from the Kerguelen region.—(Ergebnisse der deutschen Polar-Expeditionen.)

^{page 444 note 2} The species which has been referred to Campanularia cannot be specifically distinguished from a hydroid obtained last autumn by H.M.S. “Valorous” in Baffin's Bay. It belongs to a common group of campanularian forms; but yet the fact of identical forms occurring in such widely separated localities, though under conditions probably very similar, is one of great interest and significance, more especially as the distribution can hardly be explained, as in certain other cases, by the transporting agency of ships' bottoms. … A form which cannot be distinguished specifically from this [Campanularia (?) cylindrica], has more recently been dredged by H.M.S. “Valorous” from 60 fathoms in Baffin's Bay.—(Allman, , Phil. Trans., vol. 168, pp. 282, 284CrossRefGoogle Scholar.)

^{page 444 note 3} This species [Halecium mutilum], like H. macrocephalam, Allman, from the western part of the Gulf Stream, and H. sessile, Norman, from the Hebrides, is remarkable for the utter absence of the tubular prolongation of the lateral orifice of the internode which gives support to the hydranth in most of the species of Halecium.—(Allman, , Phil. Trans., vol. 168, p. 283Google Scholar.)

^{page 444 note 4} Of the Echinodermata collected at Kerguelen by the British Transit of Venus Expedition, E. A. Smith writes:—Opportunity was taken some pages back of exhibiting the relations of the Molluscan fauna of Kerguelen Island to that of the Falklands and Patagonia; and it was pointed out that representatives of boreal types entered into its composition. Materials for similar comparisons between the Echinodermata indigenous to the same regions scarcely exist, but such as there are, make it apparent that what obtains in the Mollusca holds good also in the Echinodermata with respect to geographical distribution. … A similarity to certain boreal terms is exhibited by some of the species. Thus Porania antarctica strangely resembles P. pulvillus of the northern seas of Europe; the Pedicellaster represents another septentrional genus; Pteraster affinis imitates closely Pt. militaris of boreal waters. The genera Ophioglypha and Ophiacantha are almost cosmopolitan in distribution; yet the Kerguelen Island representative of the former, O. hexactis, in colour and in tout ensemble approaches O. Sarsii of the Greenland coast.—(Phil. Trans., vol. 168, pp. 270–1.)

^{page 445 note 1} F. Leipolt doubtfully regards this as a synonym of Asterias ruyispinna, Stimpson, from Tierra del Fuego, Magellan Strait, and off Buenos Ayres (Zeitschr. f. wiss. Zool., Bd. lix. p. 563, 1895Google Scholar).

^{page 445 note 2} Théel considers the form named by Studer Cuvieria porifera to be possibly identical with Psolus ambulator, Bell, from Australia.

^{page 445 note 3} Grube and M'Intosh referred specimens collected at Kerguelen to the Magellan Strait species Hermadion longicirratus, Kinberg, and Hermadion magalhænse, Kinberg, but an examination of Challenger specimens from Kerguelen convinced M'Intosh that the Kerguelen species is distinct, and he named it Hermadion karguelensis.

M'Intosh considers the Serpula patagonica of Grube to be a synonym of Serpula narconcnsis, Baird.

Studer records a species of Nereis without authority (Nereis aprogenia) from Kerguelen, 100 fathoms.

^{page 445 note 4} Grube records the northern Artacama proboscidea, Malmgren, from Kerguelen; his specimens possibly belong to Artacama challengeræ, M'Intosh, which seems to be very frequent in Kerguelen waters.

^{page 445 note 5} The occurrence of this species [Harpacticus fulcus] in Kerguelen Island is particularly interesting from the fact that it is found all over the European shores in precisely similar situations, that is to say in brackish pools, at or above high-water mark, which are liable to become warm through exposure to the sun's rays. These are in no respect distinguishable from European specimens—(Brady, G. S., Phil. Trans., vol. 168, p. 215.CrossRefGoogle Scholar)

^{page 446 note 1} Pfeffer records Rhachotropis aculeatus (Lepechin) from the Kerguelen region (Ergebnisse dcr deutschen Polar-Expeditionen); this is probably the species named by Stebbing Rhachotropis kergueleni.

^{page 446 note 2} In the form of the antero-lateral angles of the cephalon, and of the postero-lateral angles of the third segment of the pleon, this species [Anonyx kergueleni] to some extent resembles (1) Hippomedon holbölli, Kröyer, as described by Boeck, as well as (2) H. abyssi, Goës, and (3) Anonyx pumilus, Lilljeborg—all from the Northern Sea. … The eyes, also, which are well marked in the species just referred to, are not visible in any of the specimens of A. kergueleni.—(Miers, E. J., Phil. Trans., vol. 168, p. 208Google Scholar.)

^{page 446 note 3} Studer's Scroll's aralis is a synonym of Serolis septemearinata, Miers, as Studer himself supposed when he published his description.

^{page 446 note 4} This species [Nymphon antarcticum = N. gracilipes] is allied to N. grossipes, O. Fab., as described by Kröyer, from the northern seas, but differs somewhat in the length of the neck, and in the proportions of the joints of the legs and appendages.—(Miers, E. J., Phil. Trans., vol. 168, p. 212Google Scholar.)

^{page 446 note 5} E. A. Smith introduces his description of the Mollusca collected by the British Transit of Venus Expedition at Kerguelen thus:—The Malacological fauna resembles generally that of the Falkland Islands and South Patagonia. More than half of the genera and seven or eight of the species found at Kerguelen Island are known to occur at those localities, and further research will probably discover a still greater number of genera and species to be common to these two, longitudinally, so widely separated localities. With respect to their latitudes the difference is unimportant, since they both range between 49° and 54° S. lat. As the Cape of Good Hope, Tasmania, and South West Australia are the nearest points of mainland, it might be. expected that some resemblance to the fauna of those countries might be observable. However, it is not so, as far as our present knowledge extends. Many of the shells from Kerguelen Island have the generally unattractive appearance, as regards coloration, which so frequently obtains in species found in cold climates. Indeed, some of them seem to be southern representatives of boreal types. The Neobuccinum, Trophon, Saxicava, Kellia, Yohhia, Radula, and Doris, are remarkable instances of similarity to northern forms.—(Phil. Trans., vol. 168, p. 167.)

In the actual state of our knowledge, the malacological fauna of Kerguelen is composed of 26 species. This fauna ig eminently austral. It is intimately related to that of New Zealand, by the presence of some common species (Purpura striata, Venus stutchburyi, Mytilus canaliculus), and by that of the genus Struthiolaria, which is also known from Australia. On the other hand, it participates in character with those of the Strait of Magellan (Siphonaria tristensis, Patella magellanica and delesserti, Kidderia minuta), of the south of Chili (Mytilus canaliculus) and of the islands in the neighbourhood of the Cape of Good Hope (Siphonaria tristensis). Finally, it presents particular characters which imprint it, in spite of its relative poverty, with a certain seal of originality. In fact, of the 25 marine species composing it, we encounter 15 which have been found to be new to science. This is a proportion of about 60 per cent., a proportion veritably enormous, which may be perhaps explained by the isolation of the Kerguelen Islands and by their almost complete state of terra incognita in a malacological sense. The unique terrestrial species which lives at Kerguelen, Helix hookeri, is assuredly one of the Helices nearest to the Antarctic circle, the existence of which is known up to the present time.—(Crosse, , Journ. de Conchyliologie, sér. 3, tom. xvii. pp. 14–15, 1877Google Scholar.)

Pfeffer records Modiolarca pusilla, Gould, and Mytilus ungulatus, Reeve, from the Kerguelen region.—(Ergebnisse der deutschen Polar-Expeditionen.)

^{page 447 note 1} At a first glance this species [Kellia consanguinea] might easily be mistaken for the European Lasæa rubra, to which it has a very great resemblance.—(Smith, E. A., Phil. Trans., vol., 168, p. 185Google Scholar.)

^{page 447 note 2} Of Mytilus edulis Smith writes:—No definite distinction can be traced in the shells (unfortunately only eleven in number) collected at Kerguelen, from specimens from the Dutch coast bought in the London market. The form of the shell (always more or less variable), colour of the exterior and interior, the hinge with the few irregular teeth, muscular scars, and the punctures in the interior towards the ventral margins, are precisely alike in both local forms. … I have closely examined the soft parts of four Kerguelen specimens, and … I find them to be exactly the same as in European specimens.—(Phil. Trans., vol. 168, p. 189.)

This common species [Mytilus edulis] has become widely distributed, and differs considerably in form, colour, and size. Hutton quotes it as occurring in New Zealand, and I have already identified it as coming from Kerguelen.—(Smith, Zool. Chall. Exp., part 35, p. 272.)

^{page 448 note 1} A Nudibranch. brought from Kerguelen Island by the Antarctic Expedition has been identified as a variety of this common European species [Doris tuberculata], by Mr P. S. Abraham, who has recently been studying the species of this genus in the national collection. He says that it possesses no characters of specific distinction from D. tuberculata, and differs from it only in a few slight and unimportant particulars attributable to mere variation. … The undetermined Doris found by Dr Kidder in tide pools at low-water in Koyal Sound will very likely prove to be the same species.—(Smith, , Phil. Trans., vol. 168, p. 183Google Scholar.)

Studer doubtfully records Doris tuberculata from Kerguelen, but Bergh considers the form referred to as probably identical with his Archidoris kerguelenensis and distinct from the northern form.

^{page 448 note 2} Of Mr Eaton's collection of Polyzoa from Kerguelen Busk writes:—The collection affords nine or ten forms previously undescribed; the remainder belong to a fauna which ranges from the southern extremity of S. America (which may be regarded as its “centre”) to New Zealand in a westerly direction, one or two species extending even farther, to Australia and the Cape of Good Hope. It is observable that no Arctic form has been brought from Kerguelen Island, although some have been met with further south, two instances of the occurrence of the Arctic Hornera lichenoides obtained during the voyage of H.M.SS. “Erebus” and “Terror” having been communicated to me by Sir J. Hooker. Mr Eaton suspects their absence may be attributed to the shallowness of the areas searched by him, the greatest depth being not more than 10 fathoms.—(Phil. Trans., vol. 168, p. 193.)

Pfeffer records Lichenopora gignonensis, Busk, and Pedicellina australis, Ridley, from the Kerguelen region (Ergebnisse der deutschen Polar-Expeditionen); in the same place he also gives Pedicellina austratis, Jullien, from the Magellan Strait region.

^{page 448 note 3} The form called by Busk in the Transit of Venus Report Caberea boryi, Audouin, he subsequently considered to be distinct from the true Caberea boryi, and he names it Caberea darwinii in the Challenger Report, where he says:—“So far as I know at present, the true Caberea boryi of Audouin is confined to the Mediterranean and Atlantic regions, as far north as our own coast, and as far south, in all probability, as the Cape (Algoa Bay).”—(Zool. Chall. Exp. part 30, p. 29.)

^{page 449 note 1} Busk records Membranipora spinosa (Quoy and Gaimard) from Kergueleii in the Transit of Venus Eeport, and in the Challenger Eeport he gives Membranipora spinosa, d'Orbigny, from Australia and South Patagonia, but he makes no mention of Kerguelen.

^{page 451 note 1} For further species known only from north and south of the tropics, and unrecorded from the intervening iropics, which do not come within the scope of this paper, see Challenger Report, Summary of Results, pp. 1446–1449.

^{page 475 note 1} Bihang til K. Scensk. Vetensk. Akad. Handl., Bd. i., No. 13, Stockholm 1873Google Scholar.

^{page 476 note 1} Bot. Chall. Exp., part iv. I. 47, pl. xxv. fig. 1.

^{page 480 note 1} This Alga has since been described by G. Pouchet as Tetraspora poucheti, Hariot (Comptes rendus des séances de la Societé Biologie, 1892).

^{page 488 note 1} 1 Since the above was written a list of the species procured in three hauls with a trawl in shallow water (6 to 21 fathoms), off the west coast of England, has been published with the view of showing the large number of species that may be captured in single hauls from the shallower zones of depth (Third Report of British Association Committee on the Marine Zoology, Botany, and Geology of the Irish Sea, Ipswich, 1895Google Scholar). The total number of species procured in these three shallow-water hauls was 189, therefore less by 10 species than were procured in the three deep-sea hauls above noted. The most marked difference in the character of the species in these series of deep-water and shallow-water hauls is the predominence of Echinodermata in the deep sea and of the Mollusca in shallow water:—54 species of Echinodermata occurring in the deep hauls, while only 18 species are present in the shallow ones; and 40 species of Mollusca occurring in the shallow hauls, while only 26 species are present in the deep ones. This comparison has been introduced with the view of calling attention to the large number of Species in these deep hauls, and not with the purpose of showing that in the deep sea species are more abundant than in shallow and shore regions of the ocean. Though, as already stated, it is recognised that the total number of species present in the whole area of depths less than 50 fathoms all over the world is greater than in deeper water, still we have good reason for believing that in high northern and high southern latitudes the reverse holds good for depths less than 25 fathoms, and that there may be a larger total number of species in deep water than quite close to the land.

^{page 493 note 1} Phycological Memoirs of the British Museum, part iii. p. 88, London, 1895Google Scholar.

^{page 494 note 1} Thomson, Wyville, Zool. Chall. Exp., vol. i., Introd. p. 47Google Scholar.

^{page 495 note 1} See ante, p. 352.

^{page 495 note 2} See Geikie, A., Text-book of Geology, ed. 3, p. 802, London, 1893Google Scholar; de Lapparent, A., Traité de Géologie, ed. 3, p. 884, Paris, 1893Google Scholar; A. C. Ramsay, Quart. Journ. Geol. Soc., 1855, p. 185; Neumayr, M., Erdgeschicht, Bd. 2, p. 193, Leipzig and Wien, 1890Google Scholar.

^{page 495 note 3} See Dubois, Eug., The Climates of the Geological Past and their relation to the Evolution of the Sun, London, 1895Google Scholar.

^{page 496 note 1} Lord Kelvin, , Popular Lectures and Addresses, ed. 2, vol. i. pp. 421–2, London, 1891Google Scholar.

^{page 496 note 2} Laplace, Exposition du Système du Monde, ed. 6, 1836.

^{page 496 note 3} Kirkwood, , “On Certain Harmonies of the Solar System,” Amer. Journ. Science, ser. 2. vol. xxxviii. p. 5Google Scholar; S. Newcomb, Popular Astronomy, p. 513.

^{page 496 note 4} Les Hypothèses Cosmogoniques, p. 32, Paris, 1886Google Scholar; see also Blandet, , Bull. Soc. géol. de France, sér. 2, t. xxv. p. 777, 1868Google Scholar.