摘要:

On a small half‐acre island at the southern end of New Zealand a study was made of a complete community of Sooty Shearwaters from the end of 1940 to the beginning of 1957. In the season 1953–54, when the greatest emphasis was put on an estimate of the population, 551 marked birds were known to have been alive. This indicated a population of around 600 adult birds. Up to the end of January or a little later, unemployed birds constituted some two‐thirds of the community. There were about 300 burrows available each year, but in about one‐third no bird was found.Three biological points stand out above all others. The first is the periodic nestling mortality, which suggests one chick is all the parents can rear even if things go well, which does not always happen. The second is the tight fit of the breeding season, with pressure to migrate near the end of it. This probably means the parents find it hard to food themselves, lot alone a chick, in the last stages, as otherwise the migratory urge would not develop so early. The third is the low annual mortality, which may be as little as 6 per cent. If so, the average expectation of further life would be around 1

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1963.tb01603.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

Three undescribed specimens ofLepidotesin the British Museum (Natural History) are illustrated, described and discussed. One specimen from the Oxford Clay of Peterborough, is referred toLepidotes leedsi.The characters ofL. leedsiare compared with those of the two other well‐established species ofLepidotesfrom the same horizon and locality. Some fragmentary material from the Kimeridge Clay of Weymouth, and previously referred toL. leedsiis reviewed. Two specimens ofLepidotesfrom the Kimeridge Clay of Cambridgeshire, represented by associated heads, are referred to a new species,L. toombsi; the characters of the new species are compared with those of the better known forms from the Solenhofen Stone of Europe.Although species ofLepidoteshave variable numbers of cheekplates, variation occurs within certain limiting numbers which distinguish two groups ofLepidotesspecies. One group has two to six cheekplates, more commonly four to six. The other group has seven or more cheekplates, and the number may be considerable in some species. The second group can be divided into two subgroups: those with the cheekplates forming a single row adjacent to the preoperculum, and those with more than one row, or an irregular mosaic of bones in front of the preoperculum. All the species described are members of the first group, but examples and figures are given of both types in the second grou

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1963.tb01604.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

Transplants of the Harding‐Passey melanoma will implant in the mouse uterus only if transferred on days 3–6 of normal pregnancy or pseudopregnancy. Should pregnancy or pseudopregnancy be accompanied by lactation, implantation of melanoma transplants is not delayed (though blastocyst implantation is delayed for about four days) but the period during which the transplants may implant is extended to at least day 8. Autografts of body‐wall muscle tissue will implant in the uterus within the same period as will melanoma transplants.Tumour cells injected in suspensions through the cervix tended to segregate into clumps more or less spaced out and implanted along the uterus. When the transplanted tissues or cell suspensions implanted, they did so invariably in the antimesometrial mucosa, at the site of normal blastocyst implantation.A decidual reaction was elicited only when the transplanted tissues remained free, or relatively so, in the uterine lumen (between days 3–6). If extensive invasion of the uterine mucosa occurred then there was no decidual reaction even though there was a strong inflammatory reaction to invasion.Decidual tissue “en bloc” is resistant to invasion by melanoma cells. Concurrently with melanoma invasion, pigment granules, from melanoma cell debris, were ingested by epithelial cells immediately adjacent to the inv

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1963.tb01605.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

The population ofHaematomyzusparasitic on the wart‐hog (Phacochoerus aethiopicus) is distinct fromH. elephantisfrom the elephants and is described as a new species. A lectotype ofHaematomyzus elephantisPiaget is designated. Possible explanations of the distribution ofH. elephantison the asiatic elephant (Elephas maximum) and the African elephant (Loxodonta africana) are given and the question whetherHaematomyzusis likely to be a primary or secondary parasite of elephants is discussed. Four hypotheses are put forward as possible explanations of the present distribution ofHaematomyzuson elephants and wart‐h

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1963.tb01606.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

The ultrasonic emissions of both adult and juvenile Lesser Horseshoe bats have been studied. Two features were observed:—The range of frequencies used by adult bats when congregated in a crowd of 60 or more does not exceed 3 Kc/s, even though their frequency of emission is of the order of 113 Kc/s. The baby bats can make sounds of echo‐location type within 3 days of birth; they open their mouths to do so when disturbed and the frequency of the sound at first is about 30 kc/s. Erratic variations in frequency take place during developm

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1963.tb01607.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

The distribution of kalyptorhynchid Turbellaria of the inter‐tidal zone found during a survey of beaches around Anglesey and the Lleyn Peninsula is listed. The following eight new species of Schizorhynchia are described and a new genusSchizochilusestablished to receive two of them:Schizochilus marcusi, Schizochilus choriurus, Schizorhynchoides coronostylus, Schizorhynchoides meixneri, Schizorhynchoides spirostylus, Thylacorhynchus vicarus, Cheliplanilla karlingi, Diascorphynchus rubrus.A further twenty‐three species are new additions to the British fauna list. Keys are given for the identification of the familes of Kalyptorhynchia and to the genera with new spec

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1963.tb01608.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY