ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1964.tb05151.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

Newborn young of the red kangaroo weighed about 750 mg. They had well‐developed nostrils and a large tongue and the forelimbs and digits of the inanus were well developed but otherwise the external features were embryonic. Sexes of the young were recognized when they were 14 to 20 days old. The young were firmly attached to the teat during the early part of pouch life, but one young removed from the teat at 43 days was able to re‐attach and another was found free when 70 days old. Observations relating to the appearance of body pigment, vibrissae and hair were made. Young about 150 days old were observed protruding their heads from the mother's pouch; they emerged temporarily at about 200 days and permanently at about 240 days. Young out of the pouch continued to suckle from the elongated teat they had used while in the pouch. Growth curves for the developing pouch young are given.In a non‐lactating female the interval between one oostrus, as diagnosed from the vaginal smear, and the next oestrus, at which mating occurred, was 37 days. The intervals between mating with the occurrence of fertilization, and post‐partum mating were 33 to 35 days. The gestation period was between 32 and 34 days. Fertilization occurred at post‐partum oestrus but the resulting offspring was not born while the earlier young occupied the pouch.If the pouch young was prematurely removed birth of a further young, resulting from post‐partum fertilization, occurred between 31 days 2 hours and 31 days 14 hours after removal. If the young was reared until it left the pouch birth occurred 230 to 252 days after post‐partum mating and in the absence of intervening mating.Parturition was observed five times in three females. During the hours before birth occurred pregnant females repeatedly cleaned the pouch by licking inside it. They also licked around the urogenital opening and one female licked the ventral surface between urogenital opening and pouch. Females sat on the base of the tail with the tail passed forwards between the hind‐legs, the legs extended forwards and the back supported by the enclosure fence while giving birth. Newborn young took about three minutes to reach the pouch after birth and there was no evidence that they were actively assisted

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1964.tb05152.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

Certain quantitative features of the primate shoulder girdle vary in phase with established muscular differences; in the Anthropoidea, between quadrupeds, semi‐brachiators and brachiators, and in the Prosiinii between quadrupeds and hangers. These contrasts, together with others not directly associated with muscular features, contribute to the efficiency of tho shoulder mochanism for the typo of locomotion practised by each group. Thus, in brachiators, where the arm is habitually raised–a process comprising rotation of the scapula by m. trapozius and m. serratus magnus, together with abduction of the humerus by in. deltoideus, the insertion of m. trapezius is disposed more laterally and is orientated more cranially than in quadrupods where the arm is seldom, fully raised. The insertion of m. serratus magnus extends more caudally in brachiators and it is orientated so that the muscle fibres are both more nearly parallel to and further away from those of m. trapozius. Again, in brachiators, m. doltoidous inserts moro distally into tho humerus than in quadrupeds. Tho habitually raised position of the arm in brachiators can also be functionally related to a more cranial orientation of the glenoid cavity and to a more lateral projection of the shoulder joint. In semibrachiators, where the arm is sometimes used as in quadrupeds and at others as in brachiators, each of these features is developed to an intermediate degree.In man, some of these characters are like those of quadrupeds, and others as in brachiators, the pattern conforming to the contrast that while the human arm can, as in brachiators, be freely raised, most movoment occurs when it is, as in quadrupeds, in tho lowered position.In the Prosimii, contrasts in those bony features between quadrupeds and hangers parallel to some extent those between quadrupeds and brachiators in the Anthropoidea. This can be related to the fact that in hangers, as in brachiators, the body weight is habitually suspended from the raised fore l

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1964.tb05153.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

Effect of fifteen hours of daylength has boon studied in two species of local finches. Increase daylength in baya weaver (Ploceus philippinus) induces gonad recrudescence practically immediately but not in the avadavat (Estrilda amandava) and the gonads in this species continue to regress in size. In Estrilda amandava there is a post nuptial period of sexual negativity which seems to operate both at the gonadal and hypophysial levels.

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1964.tb05154.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

The morphology and structure of the thymus gland is described for the first time for single specimens of the Great Indian rhinoceros (Rhinoceros unicornis), the Sumatran rhinoceros (Didermocerus sumatrensis) and the African Black rhinoceros (Diceros bicornis).

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1964.tb05155.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

In the lower intertidal zones of the river Crouch there is a wide salinity fluctuation from a minimum when they are just covered by the tide to a maximum at full tide. Isohalines of minimal salinity rise to higher shore levels as the estuary is ascended. Marine animals, therefore, restricted to life above a particular isohaline, are found higher in the intertidal zone in the upper reaches of the estuary than in the lower. This situation applies to Hydrobia ulvae which, in addition, is limited in its distribution in the higher levels of the intertidal zone by exposure to air. Since the tidal rise and fall is less in the upper reaches o f the estuary, the animals are restricted to a narrowing belt between the converging isohaline a nd high water mark. Within this belt, however, passive stranding controls the distribution o the animals.Experimental evidence suggests that the upstream distribution of H. ulvae is controlled primarily by the effects of salinity upon the activity of the animals in general and upon the floating response in particular. Reduced activity restricts the number of animals which float and floating is eliminated in low salinities. These influences result in the population occurring as far as the upper tidal limit of the estuary and being confined within salinity extremes which the animals can tolerate physiologically.

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1964.tb05156.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

The form and arrangement of the incisor and molar cusps on the mandibles of grasshoppers varies according to the typo of food they eat and is largely independent of the taxonomic position of the species. As the grasshoppers get older their mandibles become worn and the original cusps may be completely worn away. It is possible that this may have some effect on the ability of the grasshoppers to feed, but laboratory experiments suggest that the effect is not sufficiently great to be a significant factor causing mortality.

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1964.tb05157.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

Captivity habits of Crocidura bicolor are described, including birth of a litter. PoBt‐natal development of the young was found similar to that of Crocidura hirta, though somewhat quicker. The parent, already adult when captured, lived 332 days thereafter, and her surviving male offspring died at the age of 375 days. No further breeding took plac

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1964.tb05158.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

The Soay shocp of St. Kilda is the most primitive domostic breed in Europe, resembling doinesticated Neolithic sheep and the inouflon. Those on the isle of Soay, St. Kilda are prrsumably direct descendants of the first sheep introduced to the islands in prehistoric times. Flocks stemming from them now exist in parks and other islands in Britain. A flock was established on the vacant pastures of Hirta, St. Kilda after the natives and their sheep were evacuated in 1930.

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1964.tb05159.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

The principal external features in the eight larval stages of cyprid ostraeods are described. Means of distinguishing adult from late larval stages are given. Brady's genus “Siphlocandona” is the cyprid larval stage

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1964.tb05160.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY