The walrus, Odobenus rosmarus, is a circumpolar species of arctic and sub-arctic waters and is geographically isolated into three or more morphologically distinct groups. The Eastern Canadian Arctic and West Greenland group ranged as far south as Sable Island and the Gulf of St. Lawrence in historic times, but unrestricted commercial exploitation led to a serious decline in numbers and a withdrawal of the group to the more northern and inaccessible parts of its range. The advent of the rifle into the Eskimo economy with consequent wasteful methods of hunting caused further serious reductions in the walrus herds and necessitated the introduction of restrictive hunting measures.

Two zoologists with considerable experience in the Canadian Arctic suggested to the writer that the "Gammarus Problem" would be an extremely interesting subject for investigation, and one which has several advantages, for material is relatively easy to obtain, and there are a number of species available.

The islet like structures in the pancreas were first noted by Langerhans (1869) and later named after him by Laguesse (1893). That the islets produce a substance which plays a vital role in carbohydrate metabolism was suggested by subsequent investigations (Von Mering & Minkowski, 1890; Laguesse, 1893; Diamare, 1899). This substance was extracted and named 'Isletin' by Banting & Best (1922) and was found to be effective in controlling diabetes in depancreatized dogs and humans suffering from natural diabetes.

Rates of growth and the multiple factors affecting them are of primary concern to those involved with the production of food, both plant and animal, for human populations. Knowledge of critical factors influencing growth is of use in farming animals and plants because some of these factors can be directly controlled. This knowledge is also useful in dealing with crops growing in situations where most of the factors in the environment are at present outside the influence of man, including many commercial forms of marine fish.

The work which forms the subject of the present essay was carried out in the Zoological Laboratories of McGill University, during parts of the summer vacations of the years 1903-04. The subject for investigation and the material were given me by Professor MacBride, who suggested that a comparison be made with the developement of Asterina gibbosa to see how far it might bear out his own work on Asterid development.

The redfish (Sebastes marinus L.) is a member of the family Scorpaenidae, the members of which are commonly called rockfishes. This family has a very wide distribution and is confined to salt water. The majority of the recorded species are found in the temperate Pacific waters, while only a few species occur in the North Atlantic. Of these, the species of most economic importance is the redfish (S. marinus L.). There is considerable confusion in the literature as to the number of species of Sebastes which occur in North Atlantic waters.

The metabolic rate in poikilotherms, or ectotherms, is greatly influenced by changes in the environmental temperature. Insects, in most cases, may be considered to be typically poikilothermic. There exists a specific response in metabolic rate to changes in temperature, under specific conditions. The response of insect metabolism to temperature, within the limits of the effective temperature range, traces an unbroken curve when the oxygen consumption per unit weight is plotted against temperature. The effective temperature range has been defined by R. N. Chapman (1931) as the range within which the metabolism of an insect is not actually inhibited by adverse temperature.

This quotation is taken from an address given by Dr. Gerrit Bevelander to the Third Conference on Metabolic Interrelations at New York, on the topic, "Some histochemical observations on the development of membrane bone". In view of this lack of information on intramembranous ossification noted in the above quotation, it seemed that an investigation of this less complex type of bone development would contribute to our understanding of the formation of osseous tissue. [...]

Previous work is summarized, and breeding records from northern Canada are plotted on range maps. The data accumulated in two field seasons, and the results of a study of the collections of the Canadian Museum of Natural History, indicate a closer relationship between kumlieni and thayeri, than between thayeri and smithsonianus. Both kumlieni and thayeri are assigned to the species L. glaucoides Meyer, for which diagnostic characters are presented. [...]

Present knowledge of the fundamental function of the nephron and its role in urine formation and elimination is still incomplete. The nephron bas been subdivided into a standard pattern of segments on the basis of its morphology, and various functions were ascribed to each of the segments through the results of physiological experiments (Richards, 1929). The modern expanded knowledge in the fields of physiology and biochemistry has made it apparent that the conventional segments are further subdivided into zones which divide the labour of urine formation, reabsorption and excretion.