In recent years intensive investigations on the plumage dimorphism characteristically developed in most breeds of domestic fowl have resulted in a great increase in our knowledge concerning the rôle of the endocrine glands, in particular the thyroid and sex organs, in relation to plumage differences. Since, however, the majority of these researches have been directed to the plumage exhibited by the adult bird, it is suggested that an analysis, both observational and experimental, of the earlier plumage phases shown successively from hatching to maturity might yield much valuable data concerning the nature of the hormonic stimuli involved.

Among Gasteropod Molluscs the life-histories and development of the most highly evolved members, the terrestrial Pulmonates, have been less intensively studied than those of more primitive aquatic forms. This has been due in part to the technical difficulties involved in the permanent preparation of material for study, and in part to the fact that the investigator seeking for primitive features of phyletic interest is more likely to find these among more generalised species of Gasteropods than among those which are obviously adapted, both during the early stages of their development and in adult life, to a habitat far removed from the ancestral one.

It is the purpose of this paper to present data bearing upon the life-history of a single species of land Pulmonate, Agriolimax agrestis L., to enlarge upon certain aspects of the embryology of this species, and to demonstrate the structural and functional changes of the larva which have accompanied the transition from an aquatic to a terrestrial breeding habit.

Owing to the comparatively rare occurrence of most tectibranchs it is perhaps not surprising to find that, in spite of the ever-increasing knowledge of the histological structure and functioning of the alimentary canal of molluscs, little attention has been paid in this respect to these forms. The structure of the radula and gizzard has previously aroused interest, but so far as the rest of the alimentary canal is concerned most workers have been content with a somewhat superficial description of the gross morphology such as was given by Vayssière (1880), Bouvier (1893), Pelseneer (1893, 1894), and Guiart (1901). A more recent account of the digestive tract of Philine aperta has been given by Brown (1934), but this includes no histological or physiological consideration.

Since the preliminary cytological work of Doncaster (1906) nothing has been recorded on the maturation of the thelytokously (female-producing) parthenogenetic saw-flies (Ten-thredinidæ). Doncaster worked with the four species now known, according to Enslin (1918), as Empria abdominalis F., E. pulverata Ritz., crœsus varus Vill., and Hemichroa crocea Geoffr., and he concluded (1907) that the chromosome number in the oocyte, polar nuclei and egg pronucleus was 8, there being two maturation divisions giving rise to an egg pronucleus and three polar nuclei. As stated in our note to Nature (1937) recent work on the thelytokously parthenogenetic species, Pristiphora pallipes Lep., by our colleague, Mr L. C. Comrie, confirms Doncaster regarding the number of maturation divisions and polar nuclei, but raises strong doubts on Doncaster's interpretations of chromosome number and behaviour. Doncaster did not make it clear whether the diploid number was 8 or 16, or whether auto regulation occurred during or after maturation. It appears probable that the real diploid number is 16, for intensive study of over twenty species of saw-flies, carried on mainly by Dr F. Greenshields in this department (unpublished work), shows that the characteristic diploid number for Tenthredinidæ is 16. Further, judging by Mr Comrie's research on Pristiphora pallipes, in which the diploid number is also found to be 16, it would appear probable that autoregulation in Doncaster's types is brought about by fusion of egg pronucleus and second polar nucleus.

La Scotia a recueilli, dans les régions antarctiques, un petit nombre de Crïnoides; mais cette collection, quoique restreinte, est intéressante et je regrette vivement que diverses circonstances, indépendantes de ma bonne volonté, ne m'aient pas permis d'en faire une étude complète.

Parmi les formes libres se trouvent des exemplaires se rapportant à l'Isometra vivipara Mortensen, espèce incubatrice présentant, dans des pinnules élargies à leur base, des œufs en voie de développement et dont quelques cirres portent des larves au stade pentacrine. Ces exemplaires ont été recueillis au “Burdwood Bank,” comme ceux dont Anderson (1904) avait décrit le mode d'incubation sous l'appellation d'Antedon hirsuta Carpenter et qu'Austin Clark (1915, p. 146) présumait devoir être Isometra angustipinna (Carpenter) ou une forme voisine. Mais Mortensen (1918, p. 10) examinant les échantillons rapportés par l'Expédition antarctique suédoise de cette espèce incubatrice la considére comme nouvelle et la décrit sous le nom d'Isometra vivipara.

In a previous communication (Charles, 1938) gross reproduction rates were given for the counties, cities and burghs, and for the urban and landward areas of Scotland. The present communication is an attempt to correlate differences among these rates with measurable social circumstances, more especially with occupation and with frequency of marriage. Attention will be directed mainly to such differences in 1931.

During a part of the years 1937 and 1938 a biological study of the fresh-water mollusca of the Tanganyika Territory and Zanzibar Protectorate was carried out with the aid of the grant of the Wandsworth Scholarship of the London School of Hygiene and Tropical Medicine. Up to the present little has been known about the molluscs of this part of Africa, although the importance of certain members of this group as the intermediate hosts of human blood flukes (Schistosoma spp.) has been widely recognized. The following account of the constitution and distribution of the molluscan fauna of this region may therefore be of interest and value.

Until recently the taxonomic and phylogenetic relationships of some of the Carboniferous plants in the two genera, Dactylotheca and Senftenbergia, could not be defined with any clear degree of certainty. The main reason for this was that workers who had investigated these types had failed to reveal some of their most important structural features. In the past, therefore, it has been impossible with the information available to make adequate comparisons of the types included in these genera. In a previous paper the writer (1938) showed that one at least of the three species of Dactylotheca really belonged to the genus Senftenbergia, and demonstrated that it possessed several Schizæaceous characteristics indicating its alliance with the living ferns of that family. In the present work, an analysis of the structural features of the two remaining species of Dactylotheca, and of one species of Senftenbergia has been made. These three plants are Dactylotheca Sturi Sterzel pro. var., Dactylotheca parallela Kidston, and Senftenbergia pennœformis Brongniart. The experiments on the compressions of D. parallela, however, indicate quite clearly that the plant does not belong to either the genus Dactylotheca or Senftenbergia. Its fructifications were found to be of the nature of synangia and were exannulate. Of these two features, the former removes it from Dactylotheca, and the latter prevents it from being classed within Senftenbergia. For this reason D. parallela cannot be included in the Schizæaceæ, and, therefore, the analysis of its structural features is not recorded in this paper.

At the time of his death Dr Duerden was contemplating the preparation of a paper of this nature, and it is felt by Mrs Duerden that had he been able to express his wishes in this connection he would appreciate a record of the conclusions made by him. No one realised more than Dr Duerden himself the gaps which are still present in our knowledge and interpretation of the grouping of follicles and fibres in the mammalia, and this work is certainly not meant to be taken as representing Dr Duerden's final view or those of his colleagues at the Wool Industries Research Association. In view of the unique value of much of the material the present notes are intended, therefore, to form a basis and reference, firstly, for workers engaged in the general development of any mammalian coat from a morphogenic and phylogenetic point of view, and secondly, for those interested particularly in factors concerned in the formation of different types of fleeces in sheep. The conception of the follicle bundle as a discrete and basic genetic unit largely determining the initial form of the wool staple is of the highest importance in studies on the inheritance and developmentof fleece characters.

The author summarises recent reports regarding the appearance in Mesozoic rocks of Blanckenhorn's genus Dictyoconus, long supposed to have originated in the Middle Eocene. He figures and describes the best known of these Mesozoic forms, in order to place its age and generic attribution beyond question, and discusses the problem of its relationship to allied genera as affected by its early appearance. He then describes d'Orbigny's contemporary (Cretaceous) genus Orbitolina, with which Dictyoconus has often been confused, in order to show its radical difference in structure and the characteristics of forms which can be more justly regarded as related to it. He also discusses the genotype of Orbitolina, since the species lately quoted as such is unsuitable.

The collection of Actiniaria and Zoantharia made by the Scottish National Antarctic Expedition contains nineteen species, one of which, Porponia antarctica Carlgren, I described as a new species in 1914. In all there were six species from the Antarctic, three from the Falkland Islands, six from the west coast of Cape Province, three from the Cape Verde Islands, and one, not specifically determined, from Gough Island. The new species here described are Epiactis vincentina, Epiactis brucei, Sicyonis antarctica, and Palythoa vincentina. I have not thought it necessary to compile a complete list of the literature and synonyms of the species, since in the papers cited full information is given.