摘要:

The behaviour ofDitylenchus dipsacibefore, during and after feeding on leaf tissue ofVicia fabais described. Short‐term reactions of the food cells and functions of different regions of the pharynx are described and discussed in relation to the changing pressure relationships between nematode and cel

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1976.tb04669.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

The daily variation of various behavioural activities and of plasma testosterone levels have been studied simultaneously in two groups of five domestic ducks. The social displays and sexual behaviour are essentially exhibited by the birds during the early morning (and to a lesser extent in the late afternoon for major displays). The morning corresponds precisely with the highest testosterone levels observed in the blood. As testosterone propionate injections are known to elicit social displays and sexual behaviours in ducks, it is suggested that the correlation observed between the variations of testosterone levels and of behaviour could be due to a direct effect of the variations of hormone levels on behaviour. The theoretical possibility of such a short‐term hormonal effect is briefly discusse

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1976.tb04670.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

The thyroids of four species of deer were examined with the electron micriscope and the appearance of the follicular cells are described. In particular phagolysosomes are described in relation to the secretion of thyroid hormone.

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1976.tb04671.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

The tracheal arrangement of 121 species of European Linyphiidae has been examined. Tracheal systems support the division of the family into two major groups: Linyphiinae have four simple tracheae arising from the spiracular atrium which are confined to the abdomen, whilst Erigoninae have large medial trunks which divide into numerous small branches before passing as two bundles through the pedicel to the prosoma, and short, simple lateral tracheae. In the majority of Erigoninae the medial branches are without taenidia and can be regarded as tracheoles but inHilaira, Donacochara, LeptorhoptrumandDrepanotylusthe branches possess taenidia.Allomengeais anomalous in that the medial tracheae are extensively branched but remain confined to the abdomen.Carorita, Mioxena, Wiehlea, Lessertiella, Jacksonella, Asthenargus, AphiletaandOstearius,which have been regarded as Erigoninae on the grounds of genital anatomy, all possess linyphiine tracheal systems. The significance of these findings is discussed.

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1976.tb04672.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

The genusCapitellais reviewed and eight species are recognized, with two subspecies. Redescriptions are given where appropriate. The relationship of the genus to other capitellid genera is discussed andCapitellidesis united withCapitellaand the resulting new combinations given. The value of stereoscan microscopy techniques as a taxonomic tool is discussed.

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1976.tb04673.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

The periostracum and cells lining the periostracal groove ofAnodonta cygneaL. have been studied at the electron microscope level. The cells lining the inner face of the outer fold differ in fine structural details, five cell types being recognized. Along the length of the outer surface of the middle fold, to which the periostracum is closely applied, only two cell types are evident. At the base of the periostracal groove the two epithelia are separated by a bulbous region containing a group of basal cells which initiate the periostracum. The periostracum, which is homogenously electron‐lucid, originates in the intercellular space between a basal cell and the first cell of the middle fold. It increases in thickness in the periostracal groove due to the secretory activity of the different outer fold cells. The cells of the middle fold do not appear to be involved in periostracum formatio

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1976.tb04674.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

The echiuranPrashadus pirotansisis redescribed from new material collected in the Arabian Gulf. The description greatly amplifies that of Menon&Datta Gupta (1962) and reveals an error in their original description of this species. Information is provided on habitat, zonation and feeding activities.

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1976.tb04675.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

The ArcherfishToxotesknocks aerial insects into the water by spitting at them. Spitting has been filmed and the excess pressure in the orobranchial cavity is estimated from the muzzle velocity as 7.2 kN m−2. A dissection of the head shows that the adductor arcus palatini and geniohyoideus are most likely to be involved in spitting. From measurements made of these muscles, it is calculated that stresses up to at least 210 kN m−2must act in them during spitting. Further, it appears from the calculations that these muscles must shorten at rates of 2.4‐3.0 muscle lengths sec−1, which seems unlikely at such high stresses. It is possible that a catapult mechanism may be i

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1976.tb04676.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

The purely embryonic external gill filaments of sharks consist of a single capillary loop, covered by a two‐layered epithelium with short microvilli. Towards the end of the embryonic period, the epithelial cells are filled with fibrils, about 10 nm in diameter, and mitochondria, endoplasmic reticulum and Golgi bodies disappear. The basal lamina increases in thickness, and collagen fibrils accumulate beneath. Numerous dense vesicles appear in the endothelial cell

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1976.tb04677.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Thirteen tooth eruption stages and their corresponding chronological ages are descri bed from a series of giraffe jaws. These can be used for age determination in giraffes with immature dentition. Significant correlations of the lingual crown height (r=0‐957;P<0001) and lingual occlusal surface width (r=0‐959;P<0001) with the number of dark staining incremental lines in the cementum of thin decalcified sections of the maxillary first molar were found. The regression equations derived from these relationships provide a further method for determining the age of a giraffe. A composite plate showing maxillary first molar wear patterns provides a means of roughly assigning an age to a particular specimen. Thin sections of undecalcified teeth, mandible measurements, various other indices of tooth wear and eye lens mass were investigated and found unsuitable for age determination in

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1976.tb04678.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY