The work described in the following pages was carried out in the Department of Zoology of the University of Edinburgh and at the Marine Laboratory, Plymouth. It is my pleasant task to thank the British Association for the use of their table at Plymouth, and the staffs of the Plymouth Laboratory and of the Department of Zoology at Edinburgh for help and advice; in particular, I would thank Professor J. H. Ashworth, F.R.S., under whose direction the work was carried out, for his continued aid and interest at every stage.

The animal which was used throughout the investigation was the common razor shellfish or spoutfish of our coasts, Ensis siliqua (Schumacher). The specimens studied at Edinburgh were obtained from a sandy bay at Port Seton, about ten miles below Edinburgh on the Firth of Forth; at Plymouth they were got from the east bank of the Salcombe Estuary. At both places razor shellfish were abundant at the low-water mark of spring tides, and at both Ensis siliqua was the sole species obtained.

For histological purposes small- whole animals, which were very rare, and small pieces of tissue were fixed in Bouin's fluid, in E. Allen's chromic Bouin with urea, or in corrosive sublimate and acetic mixture, and sections, cut 8 μ and 12 μ thick, were stained with Heidenhain's iron alum hæmatoxylin or in Delafield's hæmatoxylin and counter-stained with eosin.

North of Skye the waters of the Minch conceal Tertiary igneous rocks, probably of great interest, the nature of which may be surmised only from the study of a few small skerries or islands projecting above sea-level. The group of the Shiant Isles is the best known and most interesting of these, and has been described elsewhere; but the more southerly islets, which form the subject of the present communication, are not without importance in themselves, besides forming a useful geological connecting link between the Shiants and Trotternish. As shown in the sketch map (fig. 1), they comprise the little archipelago a league off the Trotternish coast, which will be referred to as the Fladda group; the island of Trodday, two miles north-east of Rudha Hunish in Skye, and three small rocks or skerries lying close to the track of the Harris mail steamer.

The present paper is the third of a series recording the results of investigations into the relations of the structures present in the oocyte during the growth period, particularly in their bearing on yolk formation. A Crustacean was selected for various reasons: firstly, as representing a large class about the oogenesis of which little is known, this in contrast to most other Arthropod groups which have been studied by several authors; secondly, in the hope that it would prove to have no yolk nucleus, and would exhibit nucleolar extrusion, a hope which has been fairly satisfactorily justified; thirdly, for the utilitarian reason that it is a common animal, easily obtainable, and able to live under laboratory conditions during considerable periods.

Despite all the evidence to the contrary, attempts have been made recently to bring Œnotheran cytology into lino with the parasynaptic theory of meiosis. Boedijn (2, 3) has described a peculiar conjugation of the chromosomes which he identifies as parasynaptic; Kihara (23) prefers to suppose the “doppelketten” origin of chromosome rings, such as he has found in Rumex; while Darlington (7) has put forward an extension of Belling's (1) hypothesis of segmental interchange.

Bellerophontidæ occur in considerable numbers at certain horizons in the Scottish Carboniferous rocks. Many forms are represented, but few have been described or figured (see Historical Account, Section III). In undertaking the study of these fossils the writer's object was limited, primarily, to figuring and describing the Scottish forms and ascertaining their value as stratigraphical indices in the Scottish Carboniferous rocks. Many forms from the shaly facies have been recorded in Scottish stratigraphical literature under the names of English and Belgian species of limestone facies. Investigation proved that most of these records were invalid, the determinations being erroneous, and that revision of all the Anglo-Belgian Bellerophontidæ was necessary in order to define the Scottish forms. The present memoir embodies the results of the wider investigation.

The work recorded in this paper forms part of an investigation to determine how far the feeding mechanism of the simple Peracaridan Hemimysis lamornæ, which we have recently described (1927), represents a primitive Malacostracan type.

We have not been able to observe any living Syncarid, but have been fortunate in obtaining preserved specimens of the three genera Paranaspides, Anaspides, and Koonunga, together with a series of transverse sections of Anaspides. From a comparison of the structure and arrangement of their mouth parts and trunk limbs with those of Hemimysis and other Malacostraca which we have observed alive, we have been able to deduce their methods of feeding in considerable detail.

The author recalls the various opinions which have been expressed as to the relationships of Blanckenhorn's genus Dictyoconus to other foraminiferal types. He shows how Dictyoconus has been affiliated to the genera Lituola, Lituonella, and Coskinolina by such authorities as Messrs Schlumberger, Douvillé, and Schubert in the past; but has since been dissociated from them by Professor Cushman in his recent monograph on the Foraminifera. The author then discusses the grounds for this dissociation, which seem to him to be inadequate; and he describes his discovery, in certain Lower Eocene beds of Northern Baluchistan, India, of numerous specimens of Didyoconus, Coskinolina, and Lituonella, mixed indiscriminately together within the same narrow limestone bands, and deceptively similar in external appearance. He describes the differences between these genera—differences which are confined to the peripheral portion of the test—and shows how sections of the three Indian forms reveal the closest agreement in their internal characters as a whole; their generic characters alone affording the means of distinguishing between them. He therefore regards these Indian forms as affording clear evidence of the close affiliation of these three genera. These Indian forms, which are the first representatives of their respective genera to be found so far east, are very similar to such western forms as Dictyoconus egyptiensis (Chapman), Coskinolina liburnica Stache, and Lituonella roberti Schlumberger and Douvillé; but they have individual peculiarities of their own, and so are described by the author as three new species.

The Leaf-spot Disease of Red Clover, which, as the name implies, confines its attacks to the leaves, is caused by the fungus Pseudopeziza Trifolii (Biv-Bern.), Fckl., (1), (7). It is responsible for the appearance, in early stages of disease, of small purplish spots, which later become brownish-yellow or black in colour. These spots ultimately bear the fruiting discs or apothecia which are found abundantly on both living and dead leaves. The disease was very prevalent, and caused considerable damage to the hay crops at the Welsh Plant Breeding Station, Aberystwyth, in 1923 and 1925. Williams (11), in his extensive studies of the clover plants at this Station, observed that in these years certain varieties were much more susceptible to the disease than others. He states that in the majority of the early varieties, which were more seriously damaged than the later, most of the lower cauline leaves were completely killed off and were shed before the crops were cut. He adds that there does not appear to bo any marked difference between the various late varieties as regards their susceptibility to this disease. The writer, from his own observations of these crops in the field, was struck by the marked frequency with which the apothecial discs occurred in clusters of from three to five in number, and accompanied, though not so frequently, by a similar cluster on the opposite side of the leaf.

The specimen to be described in this paper was presented to the embryological collection of the Anatomy Department of the University of Sydney by Dr A. A. Palmer of the Public Health Service of New South Wales.

It is a pleasant duty to acknowledge indebtedness to Dr Palmer, not only for his kindness in making over the specimen to the Department, but also for his swift recognition of its interest.

In a previous paper (4) the quantitative distribution of the molluscs and polychætes in certain intertidal muds and sands on the Scottish Coast was discussed, but there still remained several other types of shore such as (a) a river mud-flat, (b) grounds at the heads of sea lochs on the West Coast, and (c) the more exposed shores of the Western Islands, where conditions might possibly differ greatly from those already considered, with corresponding changes in the fauna. Since the publication of the first paper quantitative samples have been collected in each of these areas. Taking the survey as a whole, collections have now been made on such widely different parts of the coast that the peculiarities of the distribution of the above two groups can be stated with a fair degree of accuracy. The present paper is divided into two sections, the first dealing with the additional observations, the second with the survey as a whole.

The acquisition of a preserved fœtal specimen of the African Elephant has enabled the writer to prepare a series of papers on the anatomy of this interesting Mammal. The present paper forms Part III of the series. Part I (1926) dealt with the anatomy of the head, Part II (1928) with the body muscles. The contents of the thorax and abdomen have now been investigated, and Part III is concerned with a description of them and of the remaining parts of the skeleton. This part is the last of the series.