Several investigators have contributed to our knowledge of the development of the chondrocranium in various mammals, amongst whom Decker (1883), Gaupp (1900), Noordenbos (1905), Fawcett (1905) and Voit (1909) are the most outstanding. No attempt has as yet been made to study the chondrocranium of the camel however, due without doubt to lack of suitable material.

Development of the nasal capsule in ungulates generally has been studied in detail only by a few workers. Strum (1937), for instance, investigated the fully developed chondrocranium of Bos, while Decker (1883) and Wincza (1896) give accounts of the primordial skull of Ovis only at a particular stage in development.

Accordingly, this investigation is an attempt to describe for the first time, as far as the author can determine, the nasal capsule of the chondrocranium in Camelus dromedarius.

This paper describes the isolation and characterization of the polysaccharides synthesized by the unicellular organism, Monodus subterraneus. Complete extraction of polysaccharide material proved difficult and the method finally adopted, after removal of colouring matter by immersion in dimethyl sulphoxide, was successive extractions with (i) cold water, (ii) hot water, (iii) aqueous ethanol, (iv) chlorite solution, and (v) dilute alkali. The major polysaccharide, isolated from (v), is a glucan. It was shown by periodate oxidation, methylation and enzymic studies to consist mainly of β-l, 4-linked glucose units. The presence of a small proportion of β-1, 3-linked glucose units, either incorporated with the β-1, 4-linked units in a single polymer of the lichenin-type or in a separate polymer of the laminarin-type, was also established. Further small quantities of this mixed glucan were also deposited from (ii) and from (iii) on keeping these extracts in the cold. Heterogeneous crude polysaccharide material was isolated from (i), (ii), (iii) and (iv) by alcohol precipitation. The sugars present in these various precipitates and their respective oxopolysaccharides were identified chromatographically, and, in the case of the major constituents, separated and characterized as crystalline derivatives. The polysaccharide extracted by cold water was found to contain glucose, mannose, galactose, xylose and 12 per cent of sulphate; that extracted by hot water comprised glucose (major), galactose (major), and possibly fucose; and that extracted by chlorite solution consisted of glucose (major), xylose (major), ribose and a trace of galactose.

Two kinds of large neurones were studied in histological preparations and electron micrographs of the parenchyma of the anterior region of the body, the pharynx and the oral and ventral suckers of Fasciola hepatica. These are called the α and β neurones. The latter are larger than the α cells and vary in structure. An interstitial system composed of amorphous material of medium electron density was observed in the parenchyma, the suckers and the pharynx. Invaginations of the plasma membrane containing interstitial material extend into the β neurones and are often continuous with the nuclear envelope. It is suggested that the β cells are neuro-secretory in function and that they may be derived from the α neurones.

Information is presented on some ways in which spermatozoa vary within a mammalian species, and on the relative importance of non-genetic factors affecting this variation. The work is basic to current researches in this laboratory on the genetics of mammalian spermatozoa. Five characteristics of rabbit spermatozoa were examined in permanent nigrosin-eosin preparations: the incidence of stained spermatozoa and the incidence of spermatozoa lacking the acrosomal cap, both related to the fertility of semen; the length, breadth and area of the spermatozoan head. Various factors have been studied that potentially affect these characteristics, with emphasis on variation attributable to technique and observation. The effects of the factors have been recorded in quantitative form and, in the light of the present work, suggestions have been made for the design of future experiments. Experimental and statistical procedures are described. Observations on variation due to biological causes include a separation of the variance between the males of a litter from the variance between the litter means. It has also been shown that the average length of the spermatozoan head in the vas deferens remains virtually unchanged in the ejaculate. Mensuration characteristics (length, breadth and area) are better adapted to objective analysis than are enumeration characteristics (proportions of abnormal spermatozoa).

The stomodæum appears as an ectodermal invagination. The oesophagus develops from an outgrowth (posterior) and the radular sac from a ventral evagination of the floor of the stomodæum. The basal epithelium of the radular sac secretes the radular membrane and the teeth, while the dorsal epithelium contributes towards the hardening of the teeth. The subradular cavity is formed from a depression of the floor and the salivary glands from two evaginations of the roof of the stomodæum. The buccal cartilage is mesodermal, while the jaw is ectodermal. The blastopore closes. Only the posterior part of the archenteron takes part in the formation of the gut, from which the crop, stomach and the digestive gland develop. The anterior chamber of the crop develops from a diverticulum of the archenteron. The anterior and posterior lobes of the digestive gland arise from the anterior part of the primitive stomach dorsally and on the left side respectively; the posterior chamber of the crop from the anteroventral region of the primitive stomach, and the stomach from the posterior right side of its floor. The hind gut appears by the arrangement of cells proliferated from that part of the archenteron where blastopore closes. It opens anterodorsally into the primitive stomach in a 2½ mm. embryo; the anus appears in a late embryo about 12 days old.

Morphology and histology of the males of Acanthobonellia miyajimai (Ikeda) and Acanthobonellia vulgaris Menon and DattaGupta have been described. The males of the two species are large and look alike in all respects. Ciliated epithelium, subepidermal glands and two to four seminal vesicles are characteristics of these worms. The alimentary canal is in the form of a chain of vesicles which appear to be a common feature of Acanthobonellia, Acanthohamingia or Ikedella. Anatomical features have been described and figured.

The study of genetic effects on the phenotype of gametes may be called the genetics of gametes. As evidence of such genetic effects, marked inter-strain differences have been demonstrated in characteristics of rabbit spermatozoa examined in nigrosin-eosin preparations. Strain differences have been found in the size and shape of the spermatozoan head, and in a measure of spermatozoan viability—the incidence of stained heads. A first comparison of the spermatozoa of specific breeds is given. The size of the spermatozoan head is to some extent independent of the body weight.

A large number of density measurements of the more important rock-types exposed at the surface in Ayrshire and certain neighbouring areas provide information for the interpretation of gravity measurements. The three methods employed of determining density are (1) laboratory measurements of rock samples, (2) gravimeter measurements in mineshafts, and (3) gravimeter measurements over topographic features.

The first method, the most widely used, is the only one applicable to many of the geological formations. A total of 600 specimens measured cover all the common rock types of the Lower and Upper Palaeozoic systems and their associated igneous rocks. Use of the second method is restricted to Carboniferous rocks, in which records from four mine-shafts—Littlemill 5, Mauchline I, Auchincruive I, and Houldsworth—cover much of the Carboniferous succession in south Ayrshire. The third method was seldom applied as there are few suitable topographic features, independent of geological structure, in Ayrshire.

The results of the measurements are summarized, and their reliability discussed. Two contrasts of rock density of regional importance occur in the sedimentary succession of south Ayrshire—the first at the plane of unconformity between Upper and Lower Old Red Sandstone, and the second between Lower Old Red Sandstone and the Lower Palaeozoic greywackes. A marked contrast of local importance occurs between the Permian sandstones of the Mauchline Basin and the underlying lavas and Carboniferous rocks. In north Ayrshire the most important density contrast lies between the Upper Palaeozoic sediments and the associated dense igneous rocks—the Clyde Plateau Lavas, the Millstone Grit lavas, and the thick dolerite intrusions.

Four specimens of hermaphrodite herring are described. In three, the male portion of the gonad was at a later stage of development than the female; in the fourth both portions were fully mature and eggs and sperm were being shed together. The additional muscle block characteristic of the cloacal region of the male herring was present, but much reduced, in the two hermaphrodite fish which were examined for this character. The time difference in the maturation rates of the male and female portions is discussed in relation to the pituitary control of gametogenesis.

Monthly quantitative samples of the invertebrate fauna were taken from two stations in the River Endrick over a period of fifteen months; the substrate at one station in the lower reaches was sandy, whilst that at the other in the middle reaches was stony. The fauna at these stations differed qualitatively, but showed certain quantitative similarities, especially with regard to seasonal change. The fauna of stones is richer, and much more varied than that of sand, though both substrates appear to be unstable and may be drastically affected by spates. The average standing crop of the invertebrate fauna during 1960 was found to be 8 g. per square m. in sand and 16 g. per square m. in stones. Compared with the few other results which are available for rivers elsewhere in the world these figures would indicate that the standing crops of these substrates in the River Endrick are of intermediate richness.

In animals, the expression of genetic factors has been studied mainly after fertilization, in the embryo or the adult. The study of genetic effects on the gametes themselves has been called the genetics of gametes. As evidence of such genetic effects on gametes, numerous differences have been found in the characteristics of spermatozoa from eight inbred strains of mice. The spermatozoan characteristics studied are mainly dimensional, but also relate to the physiological maturation of spermatozoa and possibly to semen fertility. The dimensional characteristics of spermatozoa are insulated, to an unusual degree, from the effects of environmental and other factors. The genetics of gametes can be regarded as the study of the genetics of the carriers of genes from one generation to the next; this has relevance to general genetics, and also to experiments for controlling the transmission of hereditary factors from parent to offspring.

In the Sanquhar district a bsain of relatively light Upper Carboniferous rocks (relative density 2·54) overlies a denser basement of Ordovician greywackes (relative density 2·72). A gravity survey over the area with coverage of approximately one station per square kilometre, increasing to a station spacing of 100 yards along certain traverses in critical localities, shows a close relation between the Bouguer anomalies and the known geology. A local gravity low over the Carboniferous outcrop is superimposed on a steep regional gradient decreasing south-eastwards. The trend of this gradient is parallel to the strike of the Ordovician rocks, but its exact relationship to the basement structure is not clear. The residual Bouguer anomalies reflect the structure of the Carboniferous rocks; in the south-eastern part of the basin they agree closely with the calculated effect produced by the known thicknesses, structure, and density contrast. Westwards from Kirkconnel, however, there is an increasing discrepancy between the observed and the theoretical anomalies, a discrepancy which indicates the presence of an additional mass of light rock concealed under the known Coal Measures. It is inferred that this material consists of older Carboniferous strata, thickest under the present-day valley of the Nith but concealed by overstep of the overlying Coal Measures against the flanks of the basin. These hidden rocks thin gradually to the south-east across a shallow monocline with north-east trend and south-east of Kirkconnel are truncated by a large fault trending east-north-east. Both the monocline and the fault appear to affect the Westphalian strata to a lesser degree than the base of the Carboniferous rocks.

The stratigraphical significance of the concealed strata is that they evince the existence of a pre-Westphalian basin, trending north-west-south-east, which antecedes the later Hercynian fold, and also suggest that pre-Hercynian movements took place along a fault, near Kirkconnel which, trends north-east-south-west across the basin.

The previous history of Allenopithecus is summarized and a new description provided based on freshly dead cadavers of an adult male and female and of a male stillborn infant. Analysis of details of body proportions and external anatomy confirm the apartness of Allenopithecus from Cercopithecus and indicate a transitional status towards the macaques. Striking departures from cercopithecine features occur in the face, ear, extremities, in the presence, in the female, of a catamenial swelling and in the approximation or confluence, in the male, of the ischial callosities.

The expression of heritable variation in mammals is usually studied among the attributes of the adult; for example, in the body weight, milk yield, or colour of the pelt. A relatively new subject of study is that of heritable variation in the characteristics of gametes. It is of particular interest, because such variation in gametes may affect their fertility, which in turn might have repercussions on both fundamental and applied genetics. Current research is directed mainly to surveying the ways in which spermatozoa are subject to genetic influences. In the present work, heritable variations in the spermatozoa of mice are demonstrated, in the form of differences between inbred strains. The results are in virtually complete agreement with those of a previous study. It has also been found that variation in first generation crosses made from the pure strains can be largely accounted for by a blending inheritance of the characteristics of the parental types, together with an effect of heterosis. This appears to be the first demonstration in gametes of the phenomenon of heterosis, which is nearly but not quite the same as “hybrid vigour”.

Heteropneustes (Saccobranchus) fossilis Bloch. is a common airbreathing fish found in India. It possesses a respiratory sac on each side of the body embedded in the lateral myotomes. The structure of this organ, its respiratory function and the phenomenon of “drowning” when the fish is denied direct access to the air have engaged the attention of several workers in the past among whom Day (1868), Dobson (1874), Burne (1896), Das (1927), Hora (1935) and Marlier (1938) deserve mention. The only detailed account of the structure of the accessory organ of this fish is available to us from the work of Das (1927) who also paid some attention to its development. Dobson (1874) and Hora (1935) mainly concerned themselves with some experiments bearing on the “drowning” of the fish when compelled to live under water. Little information is obtainable from the existing literature on the following points which have an important bearing on evolution of its accessory respiratory organs:

(i) the gross and minute structure of the respiratory sac, especially its vascularization;

(ii) the origin and derivation of the accessory respiratory organs (=the “Fans” and the respiratory sac); and

(iii) the muscles concerned with its breathing movements.

Physical and chemical methods of analysis suitable for volumes of Drosophila hæmolymph under I μl. are described. The osmotic pressure of hæmolymph is equivalent to 1·05 per cent NaCl. The pH is 6·6·6·7. Na+, K+, Ca2+, Mg2+, Cl− and PO3−4 occur in concentrations of 56·5, 40·2, 8, 20·8, 42·2 and 2·8 mM/1. Probably the only sugar present is trehalose. A rough analysis for amino-acids indicates that they contribute an amount to the osmotic pressure equivalent to about 0·4 per cent NaCl. These results are discussed in relation to tissue culture.

Details are given of two more Giant Squids (Architeuthis) found in the Scottish area. The question of which species occur is discussed. It is suggested that the two species, A. harveyi Verrill and A.princeps Verrill, described from the American side, do not occur on the European side, as certain identifications would suggest. The two species found on the European side would, therefore, be A. dux Steenstrup and A. clarkei Robson.

The possible effect of genes on the spermatozoa carrying them can be investigated by searching for two kinds of spermatozoa in the semen of heterozygous males. During the development of appropriate biometrical methods, it became desirable to specify more exactly the basic form of variation in size between spermatozoa sampled from the same ejaculate and mounted on the same nigrosin-eosin preparation. The present study of the head length of rabbit spermatozoa indicates that apart from rare spermatozoa with exceptional dimensions the variation of spermatozoa on a preparation follows almost completely a “normal” distribution, the variance being independent of the mean and homogeneous from one preparation to another. The coefficients of skewness (g1) and of kurtosis (g2) and the statistic k4, average close to zero, g2 and k4 being homogeneous between preparations. There is evidence of heterogeneity in skewness between preparations, but the reality of the heterogeneity is not quite certain. A potential dimorphism between spermatozoa bearing X- and Y-chromosomes is inherent in the material, but analysis showed no significant evidence of any dimorphism in head length.

Organogenesis is completed by 15 days. A modified veliger stage is present. Torsion begins at about the sixth day. The foot rudiment is first to appear. The stomodæum appears as a new structure. The salivary glands develop from the stomodæum by evaginations. The œsophagus is stomodæal, while the crop and the primitive stomach are archenteric in origin. The digestive gland develops as two outgrowths of the primitive stomach. The hind gut is formed by the cells proliferated from the closed posterior end of the archenteron. It opens into the primitive stomach in a 2·5 mm. embryo, and the anus appears very late. The proctodæum is absent. The primordium of the pericardium with the heart, definitive kidney and gonad is mesodermal. The ureter is ectodermal and arises from the mantle cavity by evagination and subsequently communicates with the kidney. Lung and mantle are ectodermal and arise by separate invaginations. The lung fuses with the mantle and loses its separate existence from about a 4 mm. embryo. The nervous system is early to appear and the sense organs, except the statocysts are late in origin. They are ectodermal. The larval organs are: velum, podocyst, larval kidney, nuchal cells and larval digestive gland. The prototroch is the rudiment of the velum. It appears in a very early embryo from the posteroventral part and marks off the anterior border of the stomodæum. The cells of the prototroch become hyaline, vacuolate and develop cilia in a 2·25 mm. embryo, and it is transformed into velum. The velum helps in driving albumen into the larval and adult digestive glands and is resorbed in the body-wall epithelium. The rudiment of the foot first appears after the completion of gastrulation, and the podocyst is differentiated from it later. It steadily increases in size, assumes a hood-like shape, exhibits contraction and relaxation movements and begins to reduce when the embryo attains 3·25 mm. size. It is completely resorbed in the foot. The larval kidneys are mesodermal in origin, appear, in a 920 μ embryo. They begin to degenerate after the formation of the functional definitive kidney and disappear in a late larva. The kidneys are U-shaped, the cells of the closed anterior and bear pseudopodia, which are almost totally replaced by cilia afterwards. The kidney opens to the exterior posteriorly. The cells become vacuolated and excretory granules accumulate in the vacuoles. The nuchal cells first appear in a 2·5 mm. embryo and are excretory. They increase both in number and size with the growth of the embryo and persist throughout the larval period. The endoderm cells of the major portion of the archenteron except a small posterior part, enlarge in size, develop vacuoles and form a larval digestive organ for the purpose of digestion of albumen. Even after the formation of the adult digestive gland, the larval digestive gland functions for a short time, then degenerates and disappears at the end of the larval life.

A squash-preparation technique for the measurement of nucleus lengths in permanent preparations of the spermatozoa of Drosophila melanogaster is described. Prefixation gave longer nuclei, but the degree of pressure used in making the squash did not affect nucleus length. Variation in nucleus length between the spermatozoa of a male was fairly high (coefficient of variation 14 per cent). Smaller, though significant, differences existed between means of males within culture bottles, but there were no significant differences between means of duplicate culture bottles. There was a little evidence of heterogeneity of within-male variances. A logarithmic transformation of data before analysis was indicated. These observations provide a hitherto missing background for planning experiments in quantitative variation designed to throw light on genetic and other factors affecting the dimensions of Drosophila spermatozoa.