摘要:

Summary.1A survey of morph frequencies inCepaea nemoralisandhortensisin a district of about 7½ by 7½ miles (12 by 12 km.) on the chalk downland at the northern edge of Salisbury Plain has shown area effects in both species similar to those described elsewhere on the Chalk by Cain&Currey (1963).2InC. nemoralisthe principal morphs involved are the pink, mid‐banded and spread‐banded forms. High frequencies of mid‐banded are found in area effects elsewhere, but in the present district there is no fixation and the five‐banded form occurs widely.3As in other districts on the Chalk, there is no correspondence of morph frequencies with type of background although predation by thrushes is widespread; visual selection is either absent or ineffective.4There is also no correspondence between morph frequencies or areas and obvious features of the environment. The size of the populations involved makes it improbable that random genetic processes are responsible for the area effects.5Some abnormal populations have been found in which variation is great and seems to include in its range characters of bothnemoralisandhortensis; these are considered to belong toC. hortensis.6A description is given of the spread‐banded condition as expressed in both mid‐banded and five

ISSN:0368-2935    

DOI:10.1111/j.1096-3642.1963.tb00483.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

Summary.1Etmcypterus spinaxL. is a small bathypelagic shark which did not exceed 52 cm. in length among 4000 specimens handled in the present series. The female grows to a larger size than the male, and the fish is ovo‐viviparous; ovulation occurs chiefly in the autumn, and parturition in late winter and early spring, the period of gestation being less than a year. The young are born at a length of 12–13 cm.2The Cirripede parasite of this fish,Anelasma squalicola(Lovén) appears to breed the year round. It probably establishes itself first in the spine‐pocket, especially that of the spine in front of the first dorsal fin; and the peduncle of the parasite, penetrating deeply into the muscles of the host, forms a ‘cavity of implantation’ convenient for the attachment of a second and exceptionally third parasite.3The parasite does not exhaust the resources of the host at first, though it appears to do so among the larger fish. The fertility of the host is significantly affected, though there is no sign of ‘parasitic

ISSN:0368-2935    

DOI:10.1111/j.1096-3642.1963.tb00484.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

Summary.Works dealing with the association of searabaeid beetles and mesostigmatic mites are shortly reviewed. In the present paper the mite fauna of 106 specimens ofCopris hispanus (Scarabaeidae)is investigated. A total of 3732 mites was collected, belonging to 17 species (10 genera, 6 families). The following species are described (or redescribed) and figured:Parasitus coleoptratorum(L.) Berlese, 1906;Parasitus copridisn. sp.;Parasitus hyper‐setosusn. sp,;Pachylaelaps hispaniBerlese, 1908;Proctolaelaps parascolytin. sp.;Alliphis halleri(G.&R. Can., 1881);Alliphis gurein. sp. The degree of specifity of the mite‐beetle association is discussed. It is suggested that there is some relation between the social organization of the beetles and the degree of mite infestation, comparable to the mite‐hymenoptera associ

ISSN:0368-2935    

DOI:10.1111/j.1096-3642.1963.tb00485.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

Summary.Corophium volutatorPallas is a small amphipod crustacean which burrows in inter‐tidal mud on the British coast, and feeds on organic detritus, mainly vegetable, by selecting particles from the mud.The alimentary canal consists of foregut, midgut and hindgut. The midgut is produced into a pair of anterior dorsal caeca, a pair of ventral caeca and a pair of posterior dorsal caeca.The cardiac stomach has a large number of chitinous plates or ridges beset with hooks and spines for the trituration of food.The pyloric stomach has long fine bristles which form an eifective filter apparatus and allow only fine particles of food to pass into the midgut, where they are digested and absorbed.The hepato‐pancreas secrete digestive enzymes and store reserve food material as oil globu

ISSN:0368-2935    

DOI:10.1111/j.1096-3642.1963.tb00486.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

ISSN:0368-2935    

DOI:10.1111/j.1096-3642.1963.tb00487.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

ISSN:0368-2935    

DOI:10.1111/j.1096-3642.1963.tb00483a.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY