摘要:

An account is given of autopsy examinations on Mammalia, Aves and Reptilia during the year 1960. Statistical analyses of results are added in the tables given. Various research problems studied during the year are briefly described.

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1961.tb05898.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

The embryonic membranes of the diprotodont marsupialsTrichosurus vulpecula, Pseudocheirus peregrinus(Phalangeridae)Protemnodon rufogrisea, Setonix brachyurusandPotorous tridactylus(Macropodidae) are described.Three egg membranes—zona pellucida, albumen layer and shell membrane—are present. The shell membrane persists for almost the entire gestation period (17.5 days) inTrichosurusand for about 20 days inSetonixwhich has a gestation period of 27 days.All species have yolk‐sac placentation and in none does the allantois take part in the formation of a placenta. The bilaminar omphalopleure (non‐vascular yolk‐sac placenta) appears early and the vascular omphalopleure comparatively late in uterine development.The amnion and allantois appear comparatively late in pregnancy. InSetonixamnion folds are not evident at 17 days and are incompletely developed at 19 days. No allantoic primordium may be recognised inSetonixat 19 days The allantois is however of comparatively large size in near term embryos ofPseudocheirus, ProtemnodonandSetonix.InPseudocheirusthe allantois reaches almost to the chorion but inProtemnodonandSetonixit is excluded from the chorion by the great development of the yolk‐sac splanchnopleure.The early embryos of all species are orientated with the head towards the anterior end of the uterus but late embryos ofTrichosurus, Pseudocheirus, ProtemnodonandSetonixhave the head towards the posterior end of the uterus. Late embryos ofPotoroushave not been studied. In all species the bilaminar omphalopleure is apposed to the anterior part of the uterine wall and separated from the posteriorly placed vascular omphalopleure by the sinus terminalis which follows an equatorial or oblique course around the inner surface of the uterine wall. A small area of true chorion is apposed to the uterine wall near the uterine neck.In all species the uterine lumen epithelium remains complete throughout pregnancy. Embryonic and maternal blood streams are separated by the two endothelia, by embryonic mesenchyme and maternal connective tissue and by embryonic ectoderm and maternal epithelium. The uterine endometrium is well vascularised inTrichosurusandPseudocheirusand in the latter embryonic and maternal blood streams are brought into close proximity by displacement of nuclei from the cell layers separating the blood vessels. In the remaining species (all macropod marsupials) the uteri are relatively avascular and embryonic and maternal blood streams are well separated.Material giving a positive periodic acid‐Schiff reaction is found in the uterine glands and appears to serve an embryotrophic function. Further P.A.S. positive material, found within the embryonic membranes, gives positive tests for glycogen. InProtemnodona considerable amount of material, consisting of degenerating cells, apparently serves a histotrophic function. The vascular omphalopleure appears to be the main organ of embryotrophic nutrition in the closing stages of pregnancy.It is suggested that yolk‐sac placentation is the primitive marsupial condition and that allantoic placentation has been evolved, within the group, in at least two

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1961.tb05899.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

The work here reported is of an investigation into the ecology and life history of a shore dwelling geophilomorph centipedeStrigamia maritima(Leach). A method of determining the age of individuals and hence the life history, is described. By analysis of monthly samples it is shown that for the purposes of insemination, egg laying and moulting, individuals migrate from their feeding grounds, which are frequently covered by the tide, to a shingle bank where more terrestrial conditions prevail. The egg‐laying period is more restricted than in terrestrial species and takes place in May and June when spring tides are at their smallest amplitude and there is consequently least danger of the eggs being immersed. When animals in the feeding zone are covered by the tide they migrate out of this zone up into the shingle bank. It is concluded that the species is able to maintain itself in the intertidal zone only by virtue of the fact that non‐saline conditions prevail at the top of the beach for much of the year. Information on the prey, predators and parasites ofS. maritimais gi

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1961.tb05900.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

The structure and development of the larval fore‐gut is described inRana ridibunda.It is shown that themanicottois formed from elements of the ventral pancreatic anlage which proliferate within the limits of the gut‐wall. The pattern of themanicottois examined in seventy‐five anuran species representing thirty genera and nine families. Three main deviations from the typically ranid plan are described: (a) persistence of amanicotto/ pancreatic bridge until late metamorphosis (e.g. inHeleophryne rosei); (b) restriction ofmanicottotissue to the pancreatic half of the gut tube (Alytes obstetricans) and (c) concentration of the gland into a discrete, muscular fore‐gut diverticulum (Philautus gryllus). In (b) and (c) specialized mechanisms for sorting gut contents are also described. Defined regions of the fore‐gut are examined for enzyme action. It is shown that themanicottofunctions proteolytically at ≑ pH 7.8. No such activity is detectable in any other part of the fore‐gut and tests for amylase and lipase are negative for all regions. Peptic action is first detectable about two days before the end of metamorphosis, approximately six days after the cessation ofmanicottoactivity. The effect of the chemical nature of the type of food taken during ontogeny is considered. It is shown that the nature of the diet has no detectable effect on either the form or the physiology of the fore‐gut. The distribution of themanicottois reviewed. It is concluded that the occurrence of the gland is neither a correlate of phylogenetic relationship nor of feeding habits but that its presence results from the protraction of the early anlage stage in the development of the larval pancreas. It is suggested that the absence of a peptic digestion in anuran larvae reflects a need for chloride ion economy

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1961.tb05901.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

Comparison of the femora of advanced cynodonts, tritylodonts and monotremes shows that the antero‐ventral trochanter of the cynodonts is the mammalian trochanter minor and not the reptilian trochanter internus as has been held. Consideration of the form of the pelvis supports this conclusion.The femora and pelves of anomodonts indicate that an essentially mammalian musculature was developed and that, though no trochanter minor is known in the group, an iliacus muscle must be presumed to have been developed.Among Theriodontia, the gorgonopsids are considered to have retained a largely reptilian thigh musculature, but the therocephalia and scaloposaurid bauriamorphs appear to have achieved a condition intermediate between those of reptiles and mammals.It is claimed that the femora of primitive Theria are very similar to those of advanced cynodonts and could have been derived directly from one of this type. The femora of tritylodonts and monotremes, and two of the three supposed mammalian femora from the Jurassic, are considered to be specialize

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1961.tb05902.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

The growth of the postlarval shell ofLingula unguison the north and east coasts of Singapore Island was studied. The youngest and the oldest postlarvae, observed over a period varying from one month to five years, grew in length and width all the year round. Length and width increments are inversely proportional to initial lengths and widths respectively, the linear negative correlation between increment and initial dimension being significant and high Growth is more rapid on the north than the east coast. Postlarvae transplanted to the north coast made greater increments than those left behind to grow in their original burrows on the east coast. Possible factors responsible for this difference in the rate of growth between the two localities are suggested. The regression of width increment on initial width nearly parallels that of length increment on initial length after one as well as after three years' growth, indicating a similar rate of decrease of increment with increasing initial width or length. The transformation of the shape of the shell is reflected in the changing width/length ratio. The change in width/length ratio during the postembryonic development of the shell is a continuous process. This ratio drops from a range of 1.5‐2.0 to around 0.8 during the larval stage and to around 0.4‐0.5 by the time the postlarval shell length reaches 4 mm. During the rest of the postlarval life the ratio varies sufficiently to make this an unreliable specific character forLingula unguis.The region of maximum width of the two shell valves in the same individual coincides but its relative position changes during the long postlarval stage. The shell length of the female at maturity, the maximum shell length in a sample and the longevity ofLingula unguis, are discus

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1961.tb05903.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

Three different individuals ofOctopus vulgarislaid eggs in the Society's Aquarium in September 1957, May 1960 and August 1960 respectively. Mating was observed in the first instance. The eggs were brooded for a period of thirty‐nine to forty‐two days. The larvae hatched successfully, but did not feed, although offered a variety of foods, and survived for an average of eight days. In each case the mother died immediately or shortly after the hatching of the last larvae. The behaviour of the female during brooding is descri

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1961.tb05904.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1961.tb05905.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1961.tb05906.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY