摘要:

Mesocoelium monodiDollfus (1929) occurs in amphibia and lizards includingAgama agama(L.) in Ghana. Its life cycle was studied because although over 30 species occur in this genus, the life cycle has been described imperfectly for only one other species. Tailless, stylet cercariae produced by daughter sporocysts in the digestive gland of the terrestrial gastropodLamellaxis gracilisHutton were shown to be the larvae of this parasite, when cercariae from this source which had encysted on the substratum and within the sporocyst developed into egg bearing adults after they had been fed to helminth free juvenile lizards reared from the egg in the laboratory. Metacercariae similar to those were also found in two species of ants. The anatomy of all the stages, including the adult, are described. Particular attention is paid to the considerable intraspecific variability in the adult and to changes in the size and position of the parts relative to total size. In the light of this information, it is shown that many of the characters used previously in specific diagnosis are unreliable. It is shown that the life cycle ofM. monodiclosely resembles that ofMesocoelium brevicaecumbut not those described for other species in the Dicrocoeliidae. Support can therefore be given to the inclusion of the genusMesocoeliumin a separate subfamily Mesocoeliinae, as suggested by Dollfus (1929). However, it is considered that the resemblance of the adult to other members of the Dicrocoeliidae justifies its inclusion in this family until more knowledge of the life cycles is forthcoming.

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1965.tb05217.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

The few recorded examples of injury to the persistently growing tusks of the hippopotamus are reviewed and a description is given of the distinctive deformity manifested by an additional and unique specimen. The principal pathological changes present therein are compared with those of certain malformed elephant tusks and on such a basis are interpreted as an abortive attempt at multiple tusk formation.

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1965.tb05218.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

A description of the heart ofSphenodon punctatus(Gray) based on gross dissection, serial sections and wax plate reconstruction of six specimens is given. They were found to resemble most the hearts of lacertilian reptiles. The bulbar region is only partially absorbed into the ventricle. A primary, oblique septum is present, dividing the cavity of the ventricle into acavum dorsaleand acavum ventrale.Both of these have the same relationship to the various arterial trunks as in other non‐crocodilian reptiles. Of the numerous muscle trabeculae and ridges in thecuvum dorsalenone is developed to a greater extent than the others. There is, therefore, no secondary septum in the ventricle. The coronary arteries originate from the left systemic arch to supply the bulbus and ventricle. A gubernaculum cordis is not always present but, if it is, apical coronary vessels pass through it to the ventricle.Consideration of the comparative anatomy of the heart ofSphenodonand those of other existing reptiles leads to the conclusion that it is the most primitiv

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1965.tb05219.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

The male palpal organs ofAcartauchenius scurrilis(0.P.‐C.) andSyedra gracilis(Menge) are described in detail, and the taxonomic position of the two species is discusse

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1965.tb05220.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

The development of the head and pharynx of larvae ofNeoceratodus(ranging in length from 11.5 to 34. 5 mm) was investigated form microscopic transverse serial sections. The structures studied included the chondrocranium and visceral arches, ossifications, cranial and anterior spinal nerves, musculature and vascular system. These components ofNeoceratodusare compared with similar ones, likewise investigated, inRana temporariaandRana esculenta(33 and 26 mm long, respectively), and in various genera of Urodela, either previously investigated by the author or by reference to the earlier literature.Some new homologues of the various morphological components of the head and pharynx of these groups are suggested.On the basis of the larval structure an assessment is made of the classical view of a close phylogenetic relationship betweenNeoceratodusand the two amphibian groups. it is concluded that they share a common derivation from pro‐dipnoan‐amphibian stock—of crossopterygian ancestry—in the early Devonian: a conclusion which supports an earlier somewhat similar view of Goodrich.It is further considered that there is evidence of a quasi parallel evolution betweenNeoceratodusand Urodela, though some assumed similarities in larval structure are spurious; nevertheless, in some ways, they are more similar than areNeoceratodusand members of the Anura.A common origin ofNeoceratodus(Dipnoi) and the amphibian groups supports the vie of a monophyletic derivation of the Te

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1965.tb05221.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

The larval development ofOithonina nana(Giesbrecht) is described, noting how this differs from the development ofOithona similisandO. spinirostris.A key is given to its naupliar stages. The descriptions are based on individuals hatched and reared in the laboratory; in these experiments the duration of the life cycle has been shown to be dependent on temperature.

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1965.tb05222.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

A survey made of the incidence of flight polymorphism in British Corixidae has shown that 21 species, including mostSigaraandCorixaspecies, are polymorphicf or flight only in the development of the flight musculature; a further four species are polymorphic in wing development as well. Only seven species appear to lack flight polymorphism. The differences in the morphs in muscle and cuticle development are described. The differences result from the absence of teneral development in flightless morphs. Some aspects of the thoracic morphology are compared. The species are arranged in series on the basis of changes in the musculature and the degree of reduction of cuticle pigmentation.

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1965.tb05223.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

Information upon the distribution and biology of the Muridae occurring in Nyasaland (now the Malawi Republic) was obtained mainly from collections made between February 1962 through June 1963, when a total of 13,190 trap nights and 4417 trap days were expended. Approximations of relative abundance in various areas were made by using standard trap lines. Species only recorded in areas with mean annual rainfall at least 60 inches wereLophuromys flavopunctatus, Praomys jacksoni and Thamnomys cometes. Mus tritonwas unrecorded in areas with mean annual rainfall less than 38 inches. The greatest biomass was trapped on high rainfall plateaux where predominant species trapped were campestrial and insectivorous. In other areas, species predominant in traps were mainly fossorial and vegetarian. In 78% of the localities examined, one or two species comprised over 65% of the catch.Some details of the bionomics and breeding biology of the common species were elucidated by regular collections in selected areas throughout the annual cycle. Species studied in detail were found to have a reproductive peak during the wet or the first half of the dry season. Males were consistently larger than females excepting inT. cometes, sexual size differences were statistically significant in several species. Of the 32 species recorded, only four were purely vegetarian while six were mainly insectivorous.

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1965.tb05224.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY