摘要:

The bipartite nature of the tooth has been recently used to demonstrate the close relationship between the three existing groups of Amphibia. However, Considerable doubt has remained as to the composition of the two parts of the tooth and the way in which they are linked.It order to clearify the position the teeth inHypogeophiswere examined. It is clear that the bulk of the crown and the pedicel is composed of dentine which is produced by a continuous layer of odontoblasts. This layer of cells is also responsible for the formation of the fibrous ring which joins the two portions of the tooth. This ring is regarded as an area where the odontoblasts produce fibres and little or no matrix.

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1965.tb02020.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

With the birth of a second rhinoceros calf at Bristol Zoological Gardens, it was possible to obtain samples of rhinoceros's milk during the colostral period and subsequently at regular intervals throughout sixteen months of lactation. The chemical composition and vitamin content of the samples are reported here. The analysis shows that rhinoceros's milk contains very little fat at all times during the lactation cycle.

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1965.tb02021.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

The external morphology of all stages ofNeobisium muscorum(Leach) is described, particular attention being paid to the chaetotaxy. The morphogenesis of those, and other characters of taxonomic importance, has been followed through all the nymphal stages to the adults. On this basis we have endeavoured to estimate the possible value of certain features for future systematic work; these include the chaetotaxy of the cephalothorax and tergites, the trichobothria, the blades of the flagellae and the chaetae of the chelicerae, the teeth of the chela and the measurements and ratios of various structures. Emphasis is placed on the importance of a precise study of all stages, not only to distinguish each of them, but also to discover those specific and generic characters of real taxonomic value.The life history, based on a quantitative sampling technique, is described from data from four sites. The seasonal variations in the densities of nymphs and adults suggest that one or two generations may be produced each year. A comparison is made with continental work and the ecological and geographical implications are discussed.La morphologie externe des quatre stades (nymphes et adulte) est décrite avec un soin particulier. La comparaison des nymphes et des adultes permet au taxonomiste de suivre la morphogenèse des caractères qu'il utilise; dans une certaine mesure, il est plus facile d' apprécier la valeur taxonomique d'un caractère si la genèse en a été suivie stade par stade et si l'on connaît les limites de sa variabilité ou de sa stabilité. C'est dans ce sens que sont formulées des remarques sur la chaetotaxie du céphalothorax et des tergites, sur les trichobothries des pinces, les soies du flagelle des chélicères, les soies des chélicères, les rapports morphométriques des articles appendiculaires, la denture des pinces des pattes‐mâchoires. Ces remarques soulignent la grande importance d'une étude précise de tous les stades du développement, non seulement afin de les reconnaître entre eux, mais encore afin de découvrir la valeur taxonomique de certains caractères spécifiques, mais aussi génériques.Les variations de la densité des populations des nymphes et des adultes, leur succession au cours de l'année, l'existence d'une ou deux geanérations par an, sont exposées et commentées à l'aide de graphiques et de tableaux. Les différences écologiques relevées dans les quatre stations, permettent d'expliquer les variations de densité, les chevauchements de générations de nymphes et la disparition

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1965.tb02022.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

All stages ofNeobisium carpenteriandN. maritimumare described and compared. Details are given of the chaetal counts, measurements, ratios and morphological characters which can be used to distinguish the species. These are compared with the corresponding stages ofN. muscorum(Gabbutt&Vachon, 1965). A study of the positions of the trichobothria, on the fingers of the chelae of the three species, during successive stages, indicates the approximate place at which the increments are added at the moults. The different positioning of these growth zones results in disparities in the disposition of the trichobothria in the adult condition. The importance of the relative positions of the trichobothria, as well as the stage at which certain trichobothria first appear, are discussed briefly in relation to the systematics of this order.

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1965.tb02023.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

This paper discusses the occurence of allopreening and allopreening invitation behaviour in red avadavats, and analyses tho factors which cause these birds to groom partners. It was found that allopreening tended to be temporally linked with aggression and autopreening beaviour in the actor, but that on many occasions, no signs of aggression preceded the act of allopreening. Allopreening invitation behaviour with the head feathers fully raised occurred in situations when the inviting individual was attacked and in response to being pecked or allopreened.Alloprcening bouts which are tomporally correlated with autopreening behaviour may be a response by the groomer to the feathers of the clumping partner whon the preening tendency of the former bird is alroady activated.From tho evidence submitted, it seems as though the allopreening invitation posture elicits non‐aggressive preening in a bird which is likely to attack. It thus appears to act as an appeasement gesture; head ruffling changes the motivation of a bird tending to be aggressive. It was also found, however, that allopreening invitation behaviour may occur independently of appeasement.The evolution of the Spermestid allopreening invitation posture from a “fluffed” body posture is also disc

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1965.tb02024.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

The shell of Solemya exhibits considerable flexibility which is further enhanced by the marked extension of the periostracum beyond the calcareous portions of the valves. This fcature, more than any other, has made possible the habit, unique among bivalves, of burrowing deep within the substrate without direct contact with the water above. The inner calcareous layer of tho valves is restricted to a small area near the umbones while the outer calcareous layer is thin and contains a high proportion of organic material. The shell conchiolin consists mainly of protein, varying in composition, but much of it strengthcned by quinone‐tanning, and in ccrtain regions probably by the presence of appreciable quantities of chitin. The ligament, although superficially resembling an amphidetic structure, is opisthodetic, the extcnsion anterior to the umbones consisting of anterior outer layer only.The mantle is characterized by an extension of the outer fold of the mantle margin which has effected equally both the inner and outer surfaces of this fold. The secretory epithelium and the modified pallial musculature, contraction of which results in the intucking and plaiting of the periostracum, is dcscribed. Simple tubular oil glands open at the mantlo margin and are responsible for the water‐repellent nature of the periostracum.The form of the mantlelshell and that of the enclosed body are discussed and compared with those of other bivalves in which elongation of the mantle/shell is achieved in a different way. It is concluded that the mantlelshell of Solemya is of little value in determining its relationships, and that the greatly elongatod ligament, the edentulous hinge and the flexible shell are all adaptations to a specialized mode of l

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1965.tb02025.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY