摘要:

A diagnosis of the monostiliferous hoplonemertean genusProsorhochmusis provided and the type‐species, P.claparedii, is redescribed and illustrated from Plymouth and Anglesey material; the identification is related to Keferstein's (1862) original description. The taxonomic status of the remaining five species is re‐evaluated. It is concluded thatP. korotneffiandP. delageiare synonymous withP. claparedii, but that neither the generic nor specific position ofP. viviparus, P. albidusorP. subterraneuscan, at present, be determined. The importance of the genusProsorhochmusto studies on the origins of terrestrial nemerteans is discus

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1985.tb05641.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

After settling, the larva ofRhabdopleurasurrounds itself with a collagenous dome. Later, the zooid breaks through the wall of the dome and builds the horizontal tube part of the coenecium on to the dome.The dome is a layered structure, unknown in other parts of the coenecium. whereas the horizontal tube is made up of rings in the classical manner of the adult coenecium. The construction of these two parts is different. The techniques used to reinforce the horizontal tube show a marked similarity to the cortical bandages recently described in the fossil graptolites, and give support to the claim that they are ancestral toRhabdopleura.There are two sorts of early horizontal tube, one is a straight tube, and the other is longer and coiled. The hole in the dome through which the zooid emerges to build the horizontal tube is probably produced by a chemical boring of the zooid, and supports the hypothesis that the zooids can bore holes in shells and corals.

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1985.tb05642.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

This paper examines the composition and turnover of a population of European kestrelsFalco tinnunculusL. in the Southern Uplands of Scotland. Turnover was generally high, with most birds staying in the area for only one summer or winter. The rate at which birds arrived or left was highest in autumn and spring, and was independent of population size. During winter, breeding males were more likely to stay on their territories than females, and males that did so were more likely to retain their partners the following year. Breeding success was associated with a greater likelihood of return the following year, except in first‐year females which were unlikely to return anyway. The sex ratio was biased toward males in winter, especially in poor vole years when there were also few first‐year birds present. The study confirmed the high rate of turnover reported elsewhere in small raptors, and further indicated that the composition and turnover of the population were related to food supply and seasonal patterns of migrat

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1985.tb05643.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Pancreases from three male and three female adult Spinifex hopping mice (Notomys alexis) were studied. No correlation was found between pancreas weight and body weight. Estimations of islet tissue mass and of individual cell types were made on paraffin sections of Bouin‐fixed tissue taken from head, neck, body and tail regions of pancreas of each animal. Islet tissue mass was assessed using a linear scanning technique on sections stained with haematoxylin and eosin, and was compared with body weight. Specific cell types were assessed using a point‐intercept method, on aldehyde‐fuchsin‐stained sections for beta (β) cells, and on immunoperoxidase labelled sections for alpha (α) cells (glucagon) and delta (δ) cells (somatostatin). Positive regional differences noted were a greater proportion of islet tissue in the tail region, and a lower proportion of α cells in the head region. Alpha cells were peripherally situated in the islets.These results show some elements of agreement with a previously proposed hypothesis regarding the general patterns of arrangement of the mammalian endocri

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1985.tb05644.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

The social organization, nightly movements and nesting behaviour of Wood mice.Apodemus sylvaticus(L.), were studied by radio‐tracking 35 individuals in a deciduous wood in north‐east Scotland. The radios, which were mounted on collars and weighed 2·4 g, were only attached to mice weighing more than 20 g. During the breeding season (mid‐March to December), when all the mice tracked were reproductively active, male ranges were on average 3·6 times as big (5110 m2) as those of females (1424 m2); male ranges overlapped considerably whilst females probably maintained ranges largely exclusive of one another. The ranges of males overlapped those of females apparently at random, each male's range encompassing parts of about five to ten females' ranges. Individuals' ranges changed position with time, although no total displacements were noted. No long‐term bisexual associations were recorded. Nests appeared to be located at random within ranges, and nest sites were changed frequently. In summer, mice nested solitarily, whilst in winter they nested in groups of up to at least three. Typically, mice moved extensively over their ranges each night, males moving further between successive radio‐fixes than females, and having fewer activity loci. Throughout the year, mice occasionally left their normal home ranges on excursions, sometimes over 100

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1985.tb05645.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1985.tb05646.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

The horizontal distribution of the zooplankton in Lake Kariba was sampled by means of vertical hauls using 55 and 250 μm meshed nets. Crustacea were sparse in the main lake, but increased dramatically in the very shallow water at the end of Crocodile Creek. The composition of the zooplankton is influenced by the presence in the main lake of the Tanganyika sardine,Limnothrissa miodon, and by the large size of the dominant diatom in the phytoplankton. In the creeks the distribution can be explained by the zooplankton occurring in open spaces into which planktivorous fish do not enter because of the possibility of predation by Tiger fish (Hydrucyori) and birds.The systematic composition of the zooplankton in L. Kariba is reviewed and compared with two natural lakes and another man‐made lake. It is concluded that the zooplankton and the fishes in L. Kariba have reached approximately the specific diversity that one would expect from a similar sized natural lake in the same geographical ar

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1985.tb05647.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Plasma levels of luteinizing hormone (LH), follicle‐stimulating hormone (FSH) and prolactin were measured by radioimmunoassay in plasma samples collected from free‐living starlings,Sturnus vulgaris, trapped in nest‐boxes. By leaving some nest‐boxes undisturbed, and repeatedly destroying nests in others, birds from a single‐brooded population were trapped whilst nest‐building, incubating or feeding nestlings, at different times throughout the normal breeding season. In both males and females trapped whilst nest‐building, plasma LH and prolactin levels increased progressively from mid March until late May. In females sampled during incubation, LH and FSH levels were high throughout May but decreased in early June. Prolactin levels were highest in late May. In both males and females trapped during mid May, LH levels were highest in these birds which were nest‐building at this time and lowest in those feeding nestlings, FSH did not change significantly, and prolactin was low in those birds which were nest‐building and high in those incubating or feeding nestlings. In female starlings from a double‐brooded population, levels of LH and FSH were much lower whilst feeding the second brood than when feeding the first brood, whereas prolactin levels were similar. The results suggest that incubation and feeding behaviour inhibit the increase in LH secretion caused by increasing daylength, but stimulate prolactin secretion in excess of that caused by i

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1985.tb05648.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Samples of rabbit burrows were excavated and measured at four areas around Edinburgh. Of these, 31 burrows over 2 m long were analysed for internal structural relationships and the effect of soil composition and slope of the ground on their form. Seven variables were measured for each burrow—total length, number of entrance holes, number of junctions, number of ends, average length of sections between holes, junctions and ends, average depth and maximum depth. There are three main trends in burrow variation—size, an inverse relationship between relative number of holes and average depth, and an inverse relationship between average section length and relative number of junctions. Burrows in sand have relatively fewer holes and junctions, longer element lengths, a higher average depth and three times the enclosed volume per hole. Burrows dug into slopes have a higher average depth. Areas differed significantly in the relative number of holes and junctions, and average depth. It was concluded that an apparently complex structure could be summarized in terms of relatively few components. The chief of these, size, was largely independent of the soil and site characteristics, whereas the remaining two were dependent on the soil in which the burrow was dug. This may have implications for the ecology and behaviour of rabbits in different areas, and is relevant to the success of some rabbit control procedures such as burrow fumigation and warren ripp

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1985.tb05649.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1985.tb05650.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY