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.

Along with a note on Chonetes aff. edmundsi Williams and other associated fossils, nine new Lamellibranch species are described from what appear to be the Gutterford Burn Flagstones (Monoclimacis crenulata Zone), repeated by folding or thrusting, northwest of the North Esk reservoir and in the lower part of the Deerhope glacial-overflow valley, in the Pentland Hills. The localities occur respectively in the Midlothian and Peeblesshire parts of the Silurian sequence. The fauna represents an Upper Gala-Tarannon horizon, and is intermediate in age between Upper Llandovery and Lower Wenlock.

The concept of heritability is discussed in relation to the climatic changes which may affect the variations of age at sexual maturity in the fowl, and it is suggested that genetic and environmental variance, as expressed in the customary statistical formulation, may be largely synonymous terms.

Four groups of Brown Leghorn pullets are compared, one subject to no artificial lighting and the sub-optimal conditions of war years, a second to restricted lighting, and a third and fourth to 14-hour day length. The formal estimates of genetic and environmental variance were respectively 910 and 978, 594 and 546, 188 and 295, and 56 and 135. Further reduction of variability is apparent on subdivision into early and late hatches, heritability being apparently zero in the first case but maintained at an average level in the second.

Changes in variability substantiate the presence of genotype-environment interactions as previously reported, and similar conclusions follow from heterogeneity of regressions of age at maturity on date of hatch.

The nitrogen metabolism of both pods and seeds of Pisum sativum has been followed at sixteen stages of growth. The distribution of free amino acids and related compounds has been investigated by paper partition chromatography.

The present report is submitted as an illustration of the utility of variance and covariance analysis in the detection of specific modes of inheritance in quantitative genetics.

The techniques are discussed with reference to the existence of sex-linkage, maternal effects, non-additivity, and the confounding of these. Comparison of variance components due to male and female parents has revealed marked evidence of sex-linked variation of egg weight in a population of Brown Leghorns, but no obviously associated variation of body weight. Subsequent analysis reveals large sex-linked covariance, and it appears that sex-linked variation of body weight is masked by non-additive effects.

Similar conclusions follow from regression analysis of offspring on parent. For egg weight there is marked dependence of offspring on paternal variation, whilst for body weight, heritability from regression analysis is substantially lower than that estimated from correlations between offspring, in accordance with the existence of sex-linked and non-additive effects.

Sedimentary structures in the greywackes of Peeblesshire, including graded bedding, cross-lamination and load-cast structures, are described and their origin discussed.

Petrographically the greywackes are poorly sorted sediments composed of a variety of minerals and rock fragments. The minerals include quartz, felspar, augite and horn-blende, mica and chlorite, while the dominant rock fragments are andesites, spilites, quartz-keratophyres and granites.

Three groups of greywackes are recognized according to their mineralogy. The first, the Pyroxenous group, contains augite and hornblende. Rocks of the second group, the Intermediate group, are without these minerals, while the third group consists of rocks rich in garnet—the Garnetiferous group. These mineralogical differences are reflected in differences in the chemical analyses of the three groups. From consideration of the chemical and modal analyses it is suggested that differences in source rocks have influenced the composition of the greywackes more than variations in the intensity of alteration due to weathering and transport.

It is concluded that the greywackes have been formed from the rapid erosion of a land mass largely covered by Ordovician volcanic rocks, but also with developments of lowgrade regionally metamorphosed rocks and others resembling Torridonian arkoses. Sedimentation features are due to accumulation controlled largely by the action of turbidity currents.

Testicular material from a Blue Whale (Balœnoptera musculus Rafinesque), a Fin Whale (Balœnoptera physalus Lacepède) and a Sperm Whale (Physeter catodon L.), obtained 6–24 hours after death in the Antarctic during the whaling season 1946–47, showed that the testes of the first two animals were in the resting state and those of the third animal were active. Despite being collected some hours after death, the material has allowed estimation to be made for the first time of chromosome numbers from spermatogonia and spermatocytes in the prophase stage. The diploid and haploid numbers approximate to 48 and 24 respectively. These results are discussed along with those obtained by Makino (1948), the first worker to record counts of cetacean chromosomes, in his study of freshly fixed material from Dall's Porpoise, Phocœnoides dallii (True). They support this worker in his view that the cytological evidence indicates that Cetacea and Ungulata derive from a common source.

Some observations on spermateleosis and cell inclusions in the Sperm Whale are given.

Regarding the breeding season, the findings of previous workers are supported for the Blue and Fin Whales. That the Sperm Whale dealt with in this paper was found to be sexually active in December is support of Harrison-Matthews' view that the species has no definite sexual season or cycle.

In the Caridea, unlike the allied Euphausiacea and Penæidea, developing eggs are attached by means of a “cement” to specialized non-pinnate ovigerous setæ on pleopods 1–4; in Crangon also to periopods 4 and 5. The presence of these eggs does not prevent flexure of the abdomen and execution of backward escape movements. The form of the abdomen differs in relation to habit, and this, together with the disposition of the ovigerous setæ, which varies greatly in different genera and in different pleopods of the same species, conditions the arrangement of the egg-mass. Ovigerous setæ increase both in numbers and in length with age; so do the number of eggs which have to be attached. There is concentration in the pleopods of “cement” glands identical with the tegumental glands which secrete the epicuticle which the “cement” resembles in all respects. Ducts run into the ovigerous setæ but it remains obscure where the “cement” emerges; possibly it dissolves its way through the integument of the setæ to emerge at many places simultaneously. Attachment of eggs in the Caridea may be associated with the many different habits exhibited; the developing eggs are protected and hatch out in the often restricted environment of the parent.