摘要:

The cercaria ofApophallus brevis, the causal agent of black spot disease of trout, is described and shown to be a typical pleurolophocercous cercaria.

ISSN:1923-4287    

DOI:10.1139/cjr46d-003

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

Five species of tinamous were dissected and diagrams of the arteries in the neck and thorax prepared. All species were bicarotidinae normales, and each presented both a right ligamentum botalli as well as a ligamentum aortae. An arteria pericardia was present in one species. Similarities and dissimilarities in structure of the tinamous and gallinaceous birds are discussed with reference to possible phylogenetic relationships. Considerable similarity in arrangement-patterns of these two orders of birds exists and may be based upon structural characteristics of common origin, rather than upon an instance of parallel development. Tinamous may have a more recent origin from the ancestral form than their apparent relatives the Galliformes.

ISSN:1923-4287    

DOI:10.1139/cjr46d-004

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

An egg weighing 130 mgm. starts off with 25 mgm. of protein, of which 45% is consumed for energy up to the time of complete yolk sac absorption; for fat the corresponding figures are 9.4 mgm. and 77%. Up to the time of hatching there is no measurable decrease in either protein or fat, although recorded respiratory measurements suggest a probable loss of some 0.6 mgm. of fat. The dried embryo, when the yolk is gone, weighs 17.3 mgm. Expressed as calories, 41% of the yolk becomes living embryo and the rest is used up for metabolic purposes. Carbohydrate plays no appreciable part as an energy source. Nonprotein nitrogen increases steadily throughout development, being stored in the embryo. The carbohydrate, protein, fat sequence of energy sources, said to be of general application, could not be demonstrated; a more likely one is fat, protein, fat, protein.

ISSN:1923-4287    

DOI:10.1139/cjr46d-005

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

This paper constitutes a review and an analysis of the available literature on the effects of pressure changes upon insects. The variations of atmospheric pressure that occur are classified briefly, but the effects of pressure changes upon insects are considered from the standpoint of the reactions of insects to extremely low pressure, extremely high pressure, and slight variations in pressure. It is concluded that extreme changes of pressure exert no direct influence upon insects. On the other hand, there is evidence that slightly reduced pressure increases the rates of the development and of the various activities of insects, while slightly increased pressure does not appear to have any positive influence on these processes. A discussion of the possible role of chordotonal organs in the observed responses of some insects to fluctuating pressure is included, and some laboratory experiments are suggested that might aid in quantitative determinations of the effects of varying atmospheric pressure upon insects.

ISSN:1923-4287    

DOI:10.1139/cjr46d-006

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

The occurrence of parasites, parasitic disease, some non-parasitic diseases, and certain anomalous conditions in the Columbian black-tailed deer,Odocoileus hemionus columbianus(Richardson), in southern British Columbia is outlined. The parasitological findings are in two categories: those based upon a random sample of 40 wild deer, and those based upon 25 additional deer examined in their entirety and others in part. Twenty-five species of parasites, 8 arthropods and 17 helminths, were recovered. Comparison of parasitism in young and adult deer reveals a few differences in the species of parasites present but both age groups are almost equally susceptible to arthropods and to helminths. Five species of parasites,Cephenemyia jellisoni,Oesophagostomum venulosum,Dictyocaulus viviparus,Fascioloides magna, andNematodirus filicollis, were found to induce disease that was not infrequently fatal. Some evidence was secured that cursorial predators selectively remove the more heavily parasitized deer.Ten anomalous conditions arising from non-parasitic disease, injury, or congenital deformity are described but none of these was sufficiently frequent to take an important place in the life equation of the deer. Incidence figures are given for various anomalies of form and position of the teeth and for dentoalveolar abscesses and one instance of caries and one of paradontal disease are reported.The study did not include bacteria and viruses as agents causing disease in deer and the only pathogenic micro-organism identified wasActinomyces israeli.

ISSN:1923-4287    

DOI:10.1139/cjr46d-007

出版商:NRC Research Press    

年代:1946

数据来源: NRC