The adult antennal glands of Euphausiids have been described by Chun (1896), Zimmer (1913), Raab (1915), and Cannon and Manton (1927). In the course of an investigation into the development of these organs, undertaken by me at the suggestion of Professor H. Graham Cannon, it was discovered that they arise quite late in the life-history, whilst earlier larvæ were found to possess typical maxillary glands. This finding was not unexpected, for an inverse relationship between antennal and maxillary segmental excretory organs has been noted in the development of many Crustacea.

The Cambridge Spitsbergen Expedition, 1938 (Polar Record No. 17, p. 4), was led by L. H. McCabe for intensive geomorphological work in the Campbell Range at the head of Billen Bay, Ice Fjord. The principal work on nivation and corrie erosion (McCabe, 1939) was supplemented by topographical and geological survey, while some detailed investigations were made on the raised beaches and “soil polygons.” During this work a party of three crossed the ice divide by sledge to East Fjord, Wijde Bay, and spent ten days working from the northern side of the Stubendorff Glacier. The Stubendorff Mountains in this region were chosen for comparison of corrie erosion on account of their contrasting geological constitution. They are carved out of tough folded metamorphic rocks while the Campbell Range is formed of softer horizontal Carboniferous rocks.

The control of stomatal aperture by intensity of light, under normal conditions of water-relations of surrounding cells, has apparently been established by Nutman (1937) for coffee leaves. This control results in the closing of stomatal pores both with too little and with too much illumination. Since photosynthesis in the guard-cells is not known to decrease with increase in light intensity, up to the limit of full sunshine, some other factor or factors are suggested as coming into action.

Investigations, in the Department of Botany, Queen's University, Belfast, by three research students have progressively elucidated some of the factors concerned.

The structure of the anterior part of the alimentary canal of stenoglossan prosobranchs has been previously investigated by several workers, of whom the most important are Haller (1888) and Amaudrut (1898), although Haller's account, accurate so far as it goes, was published before there was any real knowledge of the comparative morphology of that part of the prosobranch gut. This knowledge we owe to Amaudrut, but in the case of the stenoglossan œsophagus the description which he gives is wrong, the various parts being orientated upside down.

The sphincter valve between the end sac and the duct in the antennal gland of Gammarus pulex was first described by Vejdovsky (1901) as consisting of “three cells forming a funnel-apparatus surrounded by a ring muscle.” According to this author “one can convince oneself of the muscular cell producing the fibrils of the muscular ring” (p. 382). Zavadsky (1914) confirmed the presence of fibrils, but failed to find a muscular cell apart from the valve cells, and concluded that “the muscle ring appears as a differentiation of the nephridial wall” (p. 97). Recent work by Cannon (1923, 1925, 1926, 1931, 1940) and by Cannon and Manton (1927) indicated that fibrils found in connection with a valve are invariably situated within the valve cells.

The statistical material of genetics usually consists of frequency distributions—of genes, zygotes and mating couples—from which new distributions referring to their progeny arise. Combination of distributions by random mating is usually symbolised by the mathematical sign for multiplication; but this sign is not taken literally for the simple reason that the genetical laws connecting the distributions of progenitors and progeny are inconsistent with the laws governing multiplication in ordinary algebra. This is explained more fully in § 2.

Drosophila melanogaster and D. simulans constitute one of those cases in which two almost identical phenotypes result from different genotypes. In particular, the histology of gametogenesis shows no detectable difference between the two species, nevertheless, the development of the gonads in their hybrids is so upset that invariably sterility results. In these hybrids the germ cells never go beyond the stage of oogonia or spermatogonia.

Numerous investigations have already been made on the biology of Calanus finmarchicus. The main body of data, however, has been derived from field observations, and while many and important conclusions have been drawn from such work, confirmation of some of them is required by direct experimental methods. Accurate studies on the feeding, metabolism, and breeding of Calanus can only be made on living animals in the laboratory. Some such investigations have already been made by Crawshay, Clarke, Fuller, Marshall, Nicholls and Orr, Harvey and others, but the results have sometimes been obscure owing to the difficulties encountered in keeping Calanus in really healthy condition.

In the course of our studies of reproduction of Calanus finmarchicus under laboratory conditions we noticed that all the eggs produced in our cultures were lying on the bottom of the glass dishes, and when transferred into fresh culture medium (“Erdschreiber”) or sea-water sank down relatively very rapidly. As the eggs were fertilised and healthy, and a large proportion of them developed into active nauplii (Raymont and Gross, 1942), it was obvious that the density of the living egg was considerably higher than that of sea-water.

1. Tulach Hill (1537 ft.) rises steeply from the southern side of the River Garry, about a mile to the south-west of Blair Atholl (fig. 1). It is the culminating point of a low range of hills running north-west from the confluence of the rivers Garry and Tummel and lying between Strath Garry on the north and Strath Tummel and Fincastle Glen on the south. To the west, the Tulach ridge descends in a drift-covered slope into the valley of Allt Bhaic, a northward flowing tributary of the Garry with its source in Loch Bhac.

Tradescantia pollen grains are excellent material for the analysis of X-ray effects. The influence of radiation on cell development, nuclear differentiation, as well as on chromosome structure can be studied. Extensive quantitative analyses, which primarily concern the mechanism of chromosome breaks and reunions induced by radiation, have already been made (Riley, 1936; Sax, 1938, 1940, 1941; Fabergé, 1940). The present paper contains data which show the effects of radiation on cell development, chromosome behaviour, nuclear differentiation, and pollen germination. It is expected that the data obtained will throw some light on the intricate mechanism present within the cell and show that the governing centre of this mechanism is the nucleus.

The presence upon the ulna of many birds of a row of smaller or greater tuberosities, their variety in size and conformation, and the presence of other appearances on the surface of the ulna suggested that an investigation of these variations and of the development of the structures might yield points of interest.

Owen (1848) was apparently the first (we have been unable to consult Brandt's paper, quoted by Gadow) to draw attention to these ulnar markings, related to the quills of the secondary remiges. In that year he published a schematic outline drawing of the avian forelimb. Neither in this nor in a subsequent publication (1849), however, did he describe the linear series of markings on the ulna shown in the drawing; but in 1866 he stated that “on the ulnar and anconal sides of the shaft are the rows of quill-knobs (in Raptores) for the secondaries; the anconal row is most marked in longipennate Natatores, and is the only row in many birds.” He mentioned also that this character is wanting in the flightless and some other birds. Pl. I, fig. 1, will be seen to correspond closely with his description.

In July and August 1929 the writer's father, Mr D. K. Kevan, found large numbers of a species of Lymnœa, cleaned out of a warm engine-pond in a timber yard in Leith. These snails showed much variation in the form of the shell, and this made identification difficult.

In July and August 1940 the writer revisited the locality, collected a considerable number of living snails from the pond in question, and eventually established that they belonged to the common North American species, Lymnœa (Stagnicola) catascopium, Say.

In a letter to Nature published in 1881, J. D. Dana recapitulated his reasons for suggesting, first in 1846 and on frequent occasions afterwards, that “the continents have always been continents … and have never changed places with the oceans.” This view of the permanency of continents and oceans became generally adopted by Sir Charles Lyell (1868) and other leading naturalists during the middle of the last century: it became recognised as what might be called the orthodox doctrine.

The medusa Cosmetira pilosella Forbes is known, from the work of Miss M. J. Delap, to arise from a Cuspidella hydroid (Russell, 1936). Recently I found a small fertile colony of a Cuspidella on a dead bivalve shell dredged off Brigurd Buoy in the Firth of Clyde and this later liberated young medusæ in the laboratory. These were identified as Cosmetira pilosella, thus confirming that the hydroid of C. pilosella is a Cuspidella. There is no previous description of the hydroid or of the newly liberated medusa and so a description is given below.

Stadler and Sprague in a series of papers (1936) succeeded in demonstrating by a genetical method the effect of ultra-violet radiation in maize pollen, and found that in their experiments in the X-ray series the chromosomal changes are very common, while in the ultra-violet series they are rare.

Until a few years ago the small size of the chromosomes limited the methods which could be used for their physical and chemical study. The discovery in 1933 that the salivary gland nuclei of Diptera contained giant multiple or polytene chromosomes threw the field open to the application of a variety of new techniques.

The present paper is the first step in an attempt to combine study of the genetics of coat colour in dogs with histological examination of the hairs and pigmentation, so that a picture may eventually be formed of the genetic relations of the various phenotypes, and of the processes by which the various colours are produced. Work along similar lines has been carried out by other workers on various mammals, e.g. on the mouse (Dry, 1926, 1928; Dunn, 1936; Einsele, 1937), guinea-pig (Wright and Hunt, 1918; Russel, 1939; Heidenthal, 1940), and in cattle (Bogart and Ibsen, 1938).

Among the genera of fern-like plants of Palæozoic Age there are a number which have orbicular or reniform leaflets. Detached leaflets of this form are frequently found, and it is a matter of difficulty to determine to which of several genera such fragments belong.

Under the name Cyclopteris Brongniart (1828, p. 215) described some orbicular leaflets found in Upper Carboniferous strata, and later investigators have shown that most of these leaflets were the basal or stipular pinnules (aphlebiæ) of the frond of the Pteridosperm Neuropteris. They were sessile on the rachis and had broad bases of attachment, while the shape of the pinnules on the upper parts of the frond was quite different. The Scottish fossils which will be described in this memoir are also orbicular leaflets and have been named Cyclopteris by some authors. There is evidence, however, that they were pedicillate and were not the aphlebiæ of the frond which bore them.

Water economy is a necessary complement of terrestrial life, for the limits of life upon land are, in part, determined by the organism's ability to utilize and conserve the water of its environment. For small organisms of terrestrial habit, the large surface-to-mass ratio and consequent surface evaporation makes the problem of water conservation particularly acute. It is therefore remarkable that the insects constitute the most numerous and varied group of terrestrial animals; and it follows that their success is, in large part, due to their ability to utilize and conserve water in widely divergent environments.