The main object of this paper is to give a comparative anatomical description of some British Anemones as well as to describe each individually; but the account is not so full as it was expected to be, as it was not possible to get all the species required.

In most cases the specimens were examined externally before sections were cut. Each specimen was prepared according to the usual method used with paraffin wax, and I found during the progress of the work that borax carmine was the stain which gave the most satisfactory results.

I should like to thank Miss E. de Fraine, D.Sc., Mr. F. W. Durlacher, and Mr. F. S. Wright for much assistance in the course of the work.

For specimens collected and sent I am deeply indebted to Dr. E. J. Allen and his staff at Plymouth, Miss Delap, of Valentia Island, and Monsieur Louis Fage, of the Laboratoire Arago, Banyuls-sur-Mer, France.

FAM. SAGARTIDÆ (Gosse, 1858).

“Actiniinæ with a contractile pedal disk; body-wall smooth, or provided with verrucæ or tubercles, and usually perforated with cinclides, with or without a cuticle. Tentacles usually numerous and retractile, not very long, smooth, simple and generally entacmæous, sphincter muscle characteristically well developed and mesogloeal, occasionally diffuse endodermal, or even absent. At least six pairs of mesenteries, may be fertile or sterile. Acontia present.” The above is the definition used by Haddon in “The Actiniaria of the Torres Straits” in 1898. There has been a great deal of discussion concerning this family.

C'est surtout pour étudier le développement post-embryonnaire de la Langouste commune (Palinurus vulgaris Latr.) que je me suis rendu au Laboratoire de Plymouth. L'endroit me semblait excellent parce que la Langouste n'est pas rare près des côtes dans les eaux du Devonshire et de la Cornouaille, parce qu'elle est principalement fréquente sur les fonds rocheux au-dessus desquels se dresse le phare d'Eddystone, aussi enfin, parce que le Laboratoire de Plymouth est très bien installé, avec un bateau, l'Oithona, qui peut se rendre en mer chaque jour et effectuer les pêches les plus diverses.

For several years I have felt the desire of going to Plymouth in order to gain practical knowledge of the excellent methods for rearing pelagic laræ, of marine animals, which have been worked out there, especially by the Director of the Marine Biological Laboratory, Dr. E. J. Allen. I was therefore very glad to receive last year an invitation from Dr. Allen to come and stay some time at his laboratory, and having got a grant for this purpose from the Carlsberg Fund and from the Danish Government, I had at length the desired opportunity.

The time I spent in Plymouth—from June 10th to July 15th this summer (1913)— was long enough for learning the methods, but, unfortunately, too short for having the full profit of my rearings, because several of the larvæ, take a longer time to reach their full size and still more to pass through metamorphosis. However, the results attained are not unimportant.

No less than six different species of Echinoderms were reared to a more or less advanced stage of development, according to the date at which fertilization could be undertaken, and according to the rate of growth of the different larval forms. These six species are: Asterias glaciallis, Luidia ciliaris, Ophiactis Balli, Ophiocoma nigra, Spatangus Purpureus, and Holothuria nigra. Fertilization of Echinocardium flavescens was also undertaken, but unfortunately the whole culture was destroyed by an accident, and no material was got later on of the species. Some other forms, the development of which I wanted likewise to study, e.g.Echinocardium pennatifidum, Amphiura (Ophiocnida) brachiala, Ophiopsila aranea, were not ripe at that time or sufficient material could not be got.

1. Attempts to obtain good cultures of Thalassiosira gravida in a purely artificial medium, made by dissolving in doubly distilled water Kahlbaum's pure chemicals in the proportions in which the salts occur in sea-water, adding nitrates, phosphates and iron according to Miquel's method and sterilizing the medium, have not succeeded.

If, however, a small percentage of natural sea-water (less than 1 per cent will produce a result) be added to the artificial medium and the whole sterilized excellent cultures are obtained, which are often better than any which have been got when natural sea-water forms the foundation of the culture medium.

The result appears to be due to some specific substance present in minute quantity in the natural sea-water which is essential to the vigorous growth of the diatoms. The nature of this substance it has not been possible to determine, but some evidence seems to suggest that it is a somewhat stable organic compound.

Provided the 1 per cent of natural sea-water is added, the various constituents of the artificial sea-water forming the basis of the culture medium can be varied in amount within wide limits. The salinity of the medium can also be considerably altered without serious detriment to the cultures.

The experiments recorded are of interest as furnishing another instance of the importance in food substances of minute traces of particular chemical compounds. They may also eventually throw light upon the nature of the conditions in the sea which are specially favourable to the production of plant life and therefore also of the animal life which that plant life sustains.

Durant mon premier séjour au Laboratoire de Biologie maritime de Plymouth, en qualité de “first Ray Lankester Investigator,” j'ai eu la bonne fortune de trouver un certain nombre d'exemplaires de la très curieuse forme larvaire découverte en Ecosse, prés d'Arran, par G. Brook (1889) qui lui donna le nom de trachelifer.

The experiments referred to in the following pages were carried out by the wish of the Director at the Plymouth Laboratory, between June, 1912, and February, 1913. They were undertaken with a view to keeping under observation some of the smaller zooplankton, and particularly the Copepoda, in order that they might be followed through the different stages of their life cycle. After a long series of disappointing results, the experiments were unavoidably interrupted at a time when apparently the chief obstacles to success had been located and largely overcome.

The Hydroids experimented on were Antennularia ramosa, and A. antennina.

These were cut in pieces and pressed through bolting silk, with the result that isolated cells and small cell aggregates were obtained, which soon aggregated together to form compact masses.

These restitution masses secreted a perisarc within from 12 to 18 hours.

Various changes in shape, and general retraction of the mass away from the perisarc occurred later, but even up to 60 days there was no sign of the regeneration of the hydranths.

The restitution masses consisted of ectoderm and endoderm cells, and in addition such structures as nematocysts, ova, and brokendown cells, all of which were subsequently absorbed and played no part in the future development. The ectoderm cells were relatively little damaged, and were embedded in a plasmodial mass formed by the endoderm cells.

A definite layer of ectoderm cells is formed on the surface, and thesecells secrete the perisarc.

Gradual aggregation and segregation of the endoderm cells from the plasmodial mass takes place ; and they form very definite tubules similar in structure to the coenosarcal tubules continuous with the enteric cavities of the normal hydranths. These tubules are embedded in a mass of ectoderm cells, they are convoluted and ramify in all directions. Many granules develop in the cytoplasm of these cells, and after about a month many of them have degenerated.

The ectodermal cells show no signs of degeneration, and the masses containing them have been kept alive for 60 days at the time of writing.

In none of the experiments was there any sign of the occurrence ofcell division

The mode of feeding in Amphioxus is effected by–

(1) The maintenance of a stream of water through the pharynx by rows of lateral cilia on the gill-bars.

(2) The throwing out of mucus from the endostyle on to the gill-bars to serve for entrapping food-particles.

(3) The collection of food-particles by rows of cilia on the pharyngeal surface of the gill-bars; these cilia woraSkip the foodparticles with mucus into cylindrical masses and transport such masses dorsally into the dorsal groove which carries the collected masses backwards into the digestive tract.

Thus the ciliary mechanisms on a gill-bar of Amphioxus are exactly the same as those on the gill-filaments of some Lamellibranchs, as Pecten, and some Gastropods, as Crepidula.

A subsidiary mode of food-collection is effected in the buccal cavity of Amphioxus by the ciliated tract known as the wheel organ, and Hatchek's pit, which supplies mucus for entrapping food-particles. These particles are passed on to the peri-pharyngeal bands which, conduct them in turn into the dorsal groove.

The gill of Amphioxus functions mainly as a feeding organ and a water pump, and probably not at all as an organ for aerating the blood.

The mode of feeding in Ascidians is almost exactly the same as that described above for Amphioxus. Food-collection, however, in Ascidians is effected by cilia on the papillae and similar outgrowths on the gill, and is also helped in some forms by transverse waving of the longitudinal bars, by which process the food is pushed as well as lashed towards the dorsal region of the pharynx.

Durant mon séjour au Laboratoire de Biologie maritime de Plymouth, j'ai eu l'occasion d'examiner un lot très important de Pycnogonum littorale, Ström, qui se trouvait dans les collections de l'établissement depuis le 8 juillet 1908. Ce lot ne comprenait pas moins de 3268 individus. Il avait été recueilli au Barbican Pool, vieux port de Plymouth, dans les filets de pêcheurs qui avaient fait leur capture, disaient-ils, à 200 milles O.N.O. des Iles Scilly. Les exemplaires étaient beaucoup plus nombreux, mais le Laboratoire n'avait pas cru devoir en conserver davantage.

An investigation on inheritance in hybrids between the three English species of Echinus was carried out in the Marine Biological Laboratory, Plymouth, during 1909–1912 by C. Shearer, W. de Morgan, and H. M. Fuchs. In a paper published in the Phil. Trans. Royal Soo., Ser. B, Vol. CCIV., p. 255, the results of this work were described in detail. At the time of publication, E. miliaris had been raised from the egg to maturity in the laboratory, in the course of one year, and a second generation had been obtained from these individuals, but none of the hybrid urchins had as yet reached maturity. This year, however, some of the hybrids have become sexually mature, and from them a second hybrid generation has been raised.

The urchins which have formed ripe genital products are four individuals of the cross E. esculentus X E. acutus (referred to below as EA) derived from fertilizations made in 1912. The largest of these urchins now measures 6 cm. in diameter, exclusive of the spines. On May 11th, 1914, two of these hybrids laid eggs in the tank in which they were kept. Naturally these eggs could not be used for experimental purposes, since they were deposited in the sea water of the aquarium circulation, and therefore not under sterile conditions. On June 6th I induced three of the four to deposit genital products without cutting them open, under conditions which excluded the possible presence of foreign eggs or spermatozoa. It is hardly necessary to mention here that, as in all the previous work on Echinus hybrids, the fact of the complete absence of such sperm was made certain by controls of unfertilized eggs, none of which segmented.

Early in June of this year (1914) I received from the Plymouth Marine Laboratory through the kindness of Dr. E. J. Allen, F.r.s., several Thermos flasks containing quantities of a culture of Luidia in the early blastula stage. This culture was made for me by Mr. James Gray, King's College, Cambridge, to whom, and to Dr. Allen, I desire herewith to express my indebtedness. The larvæ were little the worse of the journey to Glasgow, but it seemed to me that they showed even greater irregularities of form than might have been expected from Mortensen's (13) description of blastula formation in our species. However, in the end, abundance of perfectly typical young bipinnariæ were secured from the contents of the various flasks. The abnormal larvæ became gradually fewer through death, and those which survived could be isolated without much trouble, since they exhibited less capacity for keeping near the surface of the water than their healthier brethren. A great many of the early malformations were of the nature of double or twin formation, and it soon became evident that the teratological type in question, namely, double monstrosity, was about to receive a more varied expression, and to attain a more advanced stage in development, than it had ever before been my good fortune to find in any starfish culture.

In the accompanying illustrations two series of abnormal larvæ are figured, one at the gastrula stage (Figs. 1–11), and the other at that of the early bipinnaria (13–21). As a description is appended to each figure, only questions of general interest need be dealt with here.

The following is a preliminary account of some experiments carried out this summer at Plymouth. They were undertaken with a view to the investigation of the changes, both physical and chemical, which are induced in the egg by the entrance of a spermatozoon.

Some of the specific and differential characters of these two species have already been enumerated by Pace (1). Subsequently Norman (2) denied that these two forms were different, so that the literature on them was left in an unsatisfactory state. On investigating these two forms, however, I have obtained sufficient evidence-from the characters of the gonadial tubes, the calcareous collars, and the young of both forms-to verify the observations of Pace and to meet satisfactorily the objections put forward by Norman against them. The differential characters of these two species as given by Pace (loc. cit.) have been verified in an unpublished investigation by Mr. W. De Morgan and by the present writer.

In continuation of my researches on the entozoa of British marine fishes I spent two months (August and September, 1909) at the Plymouth Marine Biological Station. By the courtesy of the Government Grant Committee of the Royal Society, a table was placed at my disposal and all expenses in connection with the investigation were defrayed.

The anemones described in the following pages were collected by Mr. J. H. Orton, and forwarded for examination.

I. Edwardsia timida, Quatrefages.

Quatrefages obtained his specimens at Chausey, Manche, N. France, and his descriptions of E. timida and E. harassi as new species appeared in 1842 (“Ann. des Sci. Nat.” (2), XVIII). G. Y. Dixon obtained eight specimens at Malahide, Co. Dublin, and these he carefully described in 1886 (“Proc. Roy. Dublin Soc”). He also united Quatrefages' two species as E. timida. In 1889 A. C. Haddon supported Dixon's opinions and identification, gave a good figure of the mesenterial muscle characters, and contrasted these with three other British species (“ Proc. Roy. Dublin. Soc.”).

The separation of sponge spicules by the method here described has been employed by me from time to time, for some years past, with such satisfactory results that it may be recommended with confidence as a useful and time-saving method of preparing these or other minute hard structures for microscopic examination.

A hermaphrodite specimen of Amphioxus has been taken at Plymouth having one gonadial pouch filled with ova and the remaining pouches filled with sperm. This specimen closely resembles a similar one taken by Goodrich at Naples.

The liver and intestine of the Plymouth specimen are abnormal, but no parasites have been identified in the tissues to account for these abnormalities.

It is, moreover, improbable that there is any normal sex-change in Amphioxus, since three independent investigators have found very small specimens of both sexes, therefore no satisfactory explanation can be given of the occurrence of hermaphroditism in the specimen.

Amphioxus have been found to spawn in June, and larvae have beenobtained from the captive specimens.It is suggested that the club-shaped gland may secrete a substance for attaching the larva of Amphioxus to objects, and that this function may be correlated with the asymmetry shown in the early development of the Amphioxus .larva.

The present list of Polychætes is a revision of the list published in 1904, as part of the general list of the Plymouth Marine Invertebrate Fauna (Journ. Mar. Biol. Assoc., vol. vii., 1904, p. 219). It is the result of work carried on in the intervals of other researches, as opportunity offered, and there are in all probability a good many gaps still to be filled.

Jourdan was the first to describe Eloactis mazeli. In 1880 he published Recherches zoologiques et histologiques sur les Zoanthaires du golfe de Marseilles (1), and in this paper E. mazeli is described under the name of Ilyanthus mazelii. Jourdan obtained his specimen from the muddy sand of the north-eastern part of the Gulf from a depth of 60-80 metres. He compares its external characters with those of Peachia, Ilyanthus, and Halcampa; the following is a translation:–

On August 14th, 1913, a fine male specimen of Anthura gracilis was taken by the Oithona, in the young-fish trawl working at the surface at night, about six miles west of the Eddystone.