W. C. Osman Hill’s research while affiliated with Zoological Society of London and other places

Synopsis The scent-producing area of closely packed holocrine and apocrine skin-glands in Aotes has an atypical, caudal position. Whilst most of the holocrine glands open into hair follicles by ordinary short ducts, some of the ducts are elongated, opening either into follicles or on the skin surface. The holocrine and apocrine secretions, in conjunction with the peculiar splitting of individual hairs, cause felting of the pelage on the gland field. A peculiar structure of the hairs facilitates their splitting. Evolution and function of the gland field are discussed.

Synopsis Details of the anatomy of the heart and the great vessels are recorded in the following genera of prosimian Primates, Loris, Arctocebus, Perodicticus, Galago, Galagoides, Hapalemur, Lemur, Lepilemur and Propithecus , and comparison made with previously published data on Nycticebus . Special attention is drawn to the proportions, shape and mode of branching of the systemic aorta, which is of typical lemurine pattern in all but Loris and Propithecus . In the heart, attention is paid particularly to the valvular arrangements in the right atrium, where much variation has been found; to the number of pulmonary veins entering the left atrium, also a variable feature; to the internal and external morphology of the ventricles and the valvular arrangements therein. The presence of an os cordis is recorded for the first time in any Primate (viz. in Loris ), and the occurrence is mentioned of “brown” (glandular) fat sub-epicardially in Loris . The significance is discussed of the principal anatomical features.

Synopsis The subject is a very wide one and for the purposes of a single contribution some selection is essential. Much might be, indeed has been, said concerning the adaptations relating to sexual and reproductive behaviour in the Primates, notably in a long series of contributions by Zuckerman and his co-workers (especially in his summaries of 1932 and 1933). Attention might also be made to the structural adaptations associated with toilet habits. But I have restricted my remarks to three aspects alone, paying particular attention to behavioural patterns in which I have been personally interested, or structural details which I have myself made the subject of contributions to the literature. I shall confine myself to I. Adaptations associated with the Arboreal Habit; II. Adaptations connected with Dietetic Habits; III. Adaptations correlated with Social Organization.

Synopsis An account of the morphology of the external and internal reproductive organs of the females of Hapalemur and Lepilemur and of the male of Hapalemur , including some histological details in both sexes of Hapalemur , is presented. The female apparatus in Hapalemur is described here for the first time, while new concepts emerge in connection with the male genitalia of Hapalemur and the female organs of Lepilemur , both of which have been imperfectly known. The tunnelling of the large clitoris by the urethra in Hapalemur is unique among the Madagascar lemurs and parallels the condition in the suborder Lorisoidea. The female Lepilemur exhibits typically lemurine external and internal genitalia, but lacks the glandular specialisations met with in Lemur . Details of the relative positions and peritoneal relations of the uterine cornua and ovaries in different lemurine genera are discussed. In the male Hapalemur the penis agrees with that of other Lemurinæ; internally some observations of Beddard and Oudemans are confirmed and supplemented. The necessity for the taxoaomic separation of Hapalemur is considered.

Synopsis A detailed consideration of the morphology, peritoneal and topographical relations, blood supply and certain aspects of the histology of the alimentary tube are considered in these two rare lemurines, the anatomy of which has hitherto been very incompletely known. Evidence is presented of the structural apartness of Hapalemur from Lepilemur and Lemur and therefore for its separation in a separate subfamily of Lemuridæ. Differences between Hapalemur and Lepilemur are seen in the stomach, cæcum, colon, spleen, liver and gall-bladder. The resemblance of the spleen of Hapalemur to that of the marsupials proclaims its primitive status, while the fissuration and relative sizes of the main hepatic lobes show noteworthy differences in the two genera. In some respects Hapalemur approaches the Cheirogaleinæ, but cannot be included by definition within that subfamily.

Synopsis The colour-pattern of hybrids between Ara chloroptera male and Ara ararauna female (Aves, Psittaci) combines parental features with a character which is found in some more “primitive” species of the genus but does not occur in the two parent species. The anatomical significance of this “ancestral” pattern mark is discussed.