ISSN:0370-2774    

DOI:10.1111/j.1096-3642.1956.tb00442.x

出版商:Blackwell Publishing Ltd    

年代:1956

数据来源: WILEY

摘要:

SUMMARYThe animal described above agrees in its conchological characters withTornus duminyiRequien as described by Jeffreys, and listed by Winckworth asCirculus striatus(Philippi). Neither shell nor radula agrees with theCirculus striatus(Philippi) of Thiele.The mantle cavity contains a linear osphradium and a large monopectinate gill; the single kidney opening is posterior; the anus half‐way along the right side within the hypobranchial gland. In the structure of the jaws, radula and alimentary canal there is close resemblance to the rissoids. The single kidney on the left of the rectum separates the renal oviduct from the pericardium. There is no gonopericardial canal: the renal oviduct opens into the kidney. In the male the penis arises between the two cephalic tentacles and the vas deferens, a closed duct, opens at its tip; there is a prostate with an opening to the mantle cavity. The glands of the oviduct are confined to the posterior end of the mantle cavity; the duct opens some distance behind the anus. The plan of the female reproductive system conforms with that of other mesogastropods. The nervous system is characterized by a concentration of the ganglia with the exception of the viscerals.The affinities ofCirculus striatuswithTornus subcarinatus,the rissoids and the genusCyclostremaare considered. Its anatomy supports the conchological evidence for its classification close to the family Rissoidae. It should not be included in Thiele's family Adeorbidae.Correlation between the small size of this species and certain details of its anatomy is discussed.I wish to express my thanks to the Research Board, University of Reading, for the grant to cover travelling expenses to St. Jean‐de

ISSN:0370-2774    

DOI:10.1111/j.1096-3642.1956.tb00443.x

出版商:Blackwell Publishing Ltd    

年代:1956

数据来源: WILEY

摘要:

SUMMARY1A re‐examination of the alimentary tract of two species of Asiatic swiftlets(Collocalia)appears to confirm Bernstein's (1859) hypothesis that nest‐cement is produced by salivary glands. There is no sign of a crop‐gland such as occurs in pigeons and doves.2The salivary glands ofCollocaliaare relatively enormous in comparison with those of the unrelated SwallowHirundowhich has apparently similar aerial‐feeding habits yet does not cement its nest. On the other hand, the oesophageal and gastric mucosa in both genera are much the same.3A strikingly differential degree of salivary gland development is demonstrated in two species ofCollocalia(taken on the same day at the same cavern) which are said to have different breeding dates. No such difference was detected in the oesophageal and gastric epithelium of the same examples. The probability of a hormonal control of the seasonal development of the salivary glands ofCollocaliais briefly di

ISSN:0370-2774    

DOI:10.1111/j.1096-3642.1956.tb00444.x

出版商:Blackwell Publishing Ltd    

年代:1956

数据来源: WILEY

摘要:

SUMMARY1There is no significant difference between the reproduction rates of laboratory populations of Orkney Island Voles(Microtus orcadensis)existing under(a)winter day‐length (six hours) and(b)London summer day‐lengths (fifteen hours to fifteen hours twenty‐eight minutes) if abundant food is provided at ordinary such summer temperatures.2These data, and other considerations discussed, suggest that, as in birds, environmental factors other than photoperiodicity alone, probably govern the sexual cycle of some mammals.3A grouped arrangement of interstitial cells essentially similar to that occurring in birds is described. As spermatogenesis proceeds these cells expend their cholesterol‐positive lipids as do those of birds.4The seminiferous tubules do not undergo a post‐nuptial metamorphosis. Even when males are kept alone in total darkness the germ‐cells retain their integrity and do not metamorphose as do those of passerine birds under semidark

ISSN:0370-2774    

DOI:10.1111/j.1096-3642.1956.tb00445.x

出版商:Blackwell Publishing Ltd    

年代:1956

数据来源: WILEY

摘要:

SUMMARYHyphessobrycon innesi,the Neon Fish, suffers from a condition known as “Neon Fish Disease” that is invariably fatal. Study of a recent epizootic has shown that the causative agent of this disease is a species ofIchthyosporidium.The symptoms of the disease and the distribution of the parasiteIchthyosporidiumin the host tissues are described. The most heavily infected parts were the musculature and areolar tissue.Ichthyosporidiumis essentially histozoic and cytozoic. Nuclei of the host areolar tissue become hypertrophied, but those of the muscles are compressed or obliterated. Pressure effects prevent normal movements of the organs of the host.The developmental stages and life history ofIchthyosporidiumsp. inHyphtssobrycon innesiare described and illustrated.An attempt at treatment by increased water temperature and greater aeration removed superficially situated plasmodia but did not affect the deep‐seated ones.A brief summary is given of the distribution of other species ofIchthyosporidiumand of their effects on freshwater and inshore and offshore marine f

ISSN:0370-2774    

DOI:10.1111/j.1096-3642.1956.tb00446.x

出版商:Blackwell Publishing Ltd    

年代:1956

数据来源: WILEY

摘要:

SUMMARYDetailed examinations of two hitherto unknown collections of ophthalmosaurs have been made. Highly ossified specimens have been used to make a restoration of the back of the skull and to bring the occipital and otic regions into their correct relationships with the roofing bones of the skull. The bony labyrinth has been re‐interpreted. The frontal bone is described in detail. Details of post‐cranial osteology are also given, including the presence of a posterior notch in the coracoid ofO. icenicusSeeley. This species is rare, most of the known specimens being allocated to the speciesO. monocharactussp. nov. This new knowledge has been used to compare the British ophthalmosaurs with American forms from rocks of the same age and it has been shown thatOphthalmosaurus,containing two species, is separate generically fromBaptanodonwhich contains th

ISSN:0370-2774    

DOI:10.1111/j.1096-3642.1956.tb00447.x

出版商:Blackwell Publishing Ltd    

年代:1956

数据来源: WILEY

摘要:

SUMMARYThe harvest mouse was a common and occasionally abundant rodent in corn ricks around Oxford in the winter of 1954‐55. After existing as a rare species for several decades, it has apparently increased to its present abundance within one or two years. An unusual opportunity exists for the study of this most interesting mamma

ISSN:0370-2774    

DOI:10.1111/j.1096-3642.1956.tb00448.x

出版商:Blackwell Publishing Ltd    

年代:1956

数据来源: WILEY

摘要:

SUMMARYThe skull of the leptictid insectivoreIctops,from the White River Oligocene, is redescribed, and compared withEchinosorexand other primitive Erinaceidae. It is concluded thatIctopsis much more primitive than any known erinaceid, and at the same time possesses characters which indicate that the Leptictidae and Erinaceidae have specialized in divergent directions. The characters whichIctopsshares with the Erinaceidae are almost wholly primitive insectivore characters, not indicative of special relationship. The Leptictidae are therefore removed from the Erinaceoidea and placed in a separate superfamily, the Leptictoidea.A new classification of the insectivores is proposed, based on characters of the skull. The Lipotyphla are regarded as an order, with two suborders: (1)Erinaceomorpha, a primitive group consisting of the Leptictoidea and Erinaceoidea; (2)Soricomorpha, a specialized group, probably derived from an erinaceomorph ancestry, and comprizing the Tenrecoidea, Soricoidea and Chrysochloroidea. The chrysoehlorids are regarded as highly specialized derivatives of a soricomorph stock. The Macroscelididae, Tupaiidae, Lemuroidea and Dermoptera are interpreted as forming a natural group (Archonta), with an ancestry near the Erinaceomorpha. The Macroscelididae are related to the Tupaiidae, and thus to the Primates; they are in some ways more primitive than the Tupaiidae, and have developed in a divergent direction, in some respects paralleling the Erinaceidae. They are not closely related to the Lipotyphia, and are placed in a new order, Macroscelidea. The superorder Archonta thus consists of three orders: (1)Macroscelidea, (2)Dermoptera (3)Primates (including Tupaiidae).

ISSN:0370-2774    

DOI:10.1111/j.1096-3642.1956.tb00449.x

出版商:Blackwell Publishing Ltd    

年代:1956

数据来源: WILEY

ISSN:0370-2774    

DOI:10.1111/j.1096-3642.1956.tb00450.x

出版商:Blackwell Publishing Ltd    

年代:1956

数据来源: WILEY