摘要:

The major body components (bone, muscle, blubber, viscera and connective tissue) of 94 elephant seals were dissected and weighed.Seals in growth phase 3 (more than ten weeks old) had significantly more muscle and viscera and less blubber than seals in growth phases 1 and 2 (less than ten weeks old) of similar body weight. There were no significant differences in body composition between sexes before sexual maturity, but after sexual maturity was attained males had relatively more muscle, and less bone and viscera, than females.Prediction equations relating body component weight and body weight were derived by regression analysis. These were very highly significant, and could be used to estimate body composition from body weight.It was demonstrated that body length could be estimated from linear measurements of some bones, which would enable an estimate of size and composition of seals to be made from bone dimensions.

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1972.tb03110.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

Live Sei and Minke whales were observed underwater off Japan by a new method using commercial catcher boats. A non‐explosive harpoon was fired into the tail region of a whale and a diver approached the “tethered” live whale.After initial flurries, Sei and Minke whales swam steadily ahead of the catcher and could easily be approached by a diver. They took absolutely no notice of the diver. Live Sei and Minke whales kept their mouths tight shut all the time, but immediately after death the lower jaw always fell open. Little blood was emitted from the harpoon wound. The flippers were raised laterally when a whale surfaced and held against the sides of the body when it dived.The body shape of both rorqual species was streamlined and the throat region was quite flat, not in any way dilated. The classical baggy‐throated illustrations of rorqual whales do not show the true shape of live animals.Sperm whales harpooned by the same method swam about wildly, shed much blood and could not be observed und

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1972.tb03111.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

Studies were made on barnacle orientations with reference to water flow seen on Grey whales taken by the U.S. Fish and Wildlife Service in March, 1969. Water flow patterns were derived by laying cord transects along lines of barnacle orientation. Statistical evaluation of directional consistency within barnacle colonies revealed that 95% of the individuals were within 14° of a mean direction. Flow patterns were generally parallel to the long axis of the whales with modification in the areas of anterior rostrum, lips, throat, and flippers. No data were available concerning water flow on the flukes

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1972.tb03112.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

During the few days before emigration to the Palaearctic, the weight of Yellow wagtails wintering in Africa doubles. Most of the increase is due to the deposition of fat, as is well known, but a part of it is shown to result from hypertrophy of the pectoral muscles. The same applies to other Palaearctic birds, four warblers and a hirundine, that winter in Africa.Eleven subspecies ofM. flavaoccur at Lake Chad in spring. The four black‐headed ones have more restricted habitat requirements than some of the others; however, no differences in diet have been found. There is no evidence of hyperphagia and little of diet change when fattening. Broadly, the races that have farthest to migrate leave earliest, and their sexual recrudescence and fattening are early.Yellow wagtails wintering at or passing through Lake Chad breed mainly in eastern Europe (from the Adriatic to the Gulf of Finland, between about 12° and 30°E). They probably migrate on a great circle route, and during the flight lose one gram of weight, mainly fat, per 200

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1972.tb03113.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

Histological, histochemical and ultrastructural methods have been used to study gut structure and function in the cephalobaenid pentastomidReighardia sternae(Diesing, 1864).R. sternaefeeds exclusively on blood. Haemolysis of ingested erythrocytes is thought to be initiated by non‐specific esterase secreted by cells lining the posterior oesophagus. Only one other enzyme, acid phosphatase, was demonstrated; its activity is confined to the microvillar layer of the gastrodermis.Digestion appears to be largely extracellular, as large volumes of haematin form in the gut lumen after haemolysis. However, this is supplemented by a significant amount of intracellular digestion: accumulations of iron‐positive granules occur in approximately 20% of gastrodermal cells.All gastrodermal cells are alike, and all can undertake the same intracellular digestive process. This is characterized by a number of morphologically distinct stages which have been studied using the electron microscope. The iron‐positive particles distinguished under the light microscope were easily identifiable ultrastructurally. Spherical, weakly iron‐positive bodies form within the cisternae of the endoplasmic reticulum. Phagosomes containing haemoglobin, or some breakdown product of haemoglobin, apparently bud off from the termini of a labyrinth system of tubules under the microvilli and fuse with the ER to form these phago‐lysosomes. Intensely iron‐positive heterolysosomes, also present in the cytoplasm of these cells, accumulate haemosiderin particles which are thought to be released into the cytoplasm during phago‐lysosomal digestion.The ensuing complex changes in cell morphology are, apparently, related to the elimination of spent phago‐lysosomes. It has been suggested that the purpose of intracellular digestion is to provide a specific metabolite which the extracellular degradation of haemoglobi

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1972.tb03114.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

A preliminary account is given of the jump of the click beetle,Athous haemorrhoidalis(F.). The jump is normally made from an inverted position. It involves a jack‐knifing movement whereby a prosternal peg is slid very rapidly down a smooth track into a mesosternal pit. The muscles which produce this movement are allowed to build up tension by a friction hold on the dorsal side of the peg. The anatomy of this jumping mechanism is briefly described. Ciné recording showed that the jump was usually nearly vertical and could exceed 0.3m in height; the beetle normally rotated several times head over tail during a jump. The jump was produced by a very rapid upwards movement of the beetle's centre of gravity during the jack‐knifing action. In a typical jump, a 4 × 10−5kg beetle could be subjected to an upwards acceleration of 3800 m/s−2(380 g). The minimum work done and the power output of the muscles causing jumping have been calculated. A simple mechanical model has been constructed to simulate a jump, and several possible ways in which the jumping mechanism could operate have been

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1972.tb03115.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

The trophic relationships of the benthic invertebrates at two places of differing detrital content in an oligotrophic stream system were examined during a 12 month period.The sites are described and their detrital contents and other abiotic features compared.The faunal list at each site is fairly similar but certain species are more common at or restricted to one or other site. The reasons for this are briefly discussed.The predators and omnivores are in two groups: the first feed only on certain prey and are thus limited by the distribution of their prey. The others consume a wide range of prey and have wider distributions.The predator species are non‐selective in their choice of prey which are devoured in an intensity which cannot however be related to their density in the benthos.In poorer trophic conditions predators adapt by consuming a greater quantity of algae and detritus; cannibalism and interpredator‐predation occur. The prey species are more intensely consumed under poor trophic conditions.The ecology of two species of predatory Plecoptera is examined and the results indicate that competition probably occurs between t

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1972.tb03116.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

The erroneous notion that palpebral vibrissae (eyelashes) are wanting from the lower eyelid of the Rhinocerotidae is attributable to Pocock (1914), whose observations were apparently made on museum skins and mounted specimens only. Examination of living and of freshly dead specimens shows such vibrissae to be present upon both eyelids in three of the five extant rhinoceros forms, viz.Rhinoceros unicornis, Diceros bicornis, Ceratotherium simum(Cave, 1969; Van den Bergh, 1970).

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1972.tb03117.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

Data on morphologic features, habits, stratification, flight, and thermal response are presented forEidolon helvum, Epomops franqueti, andMicropteropus pusillusfrom Rio Muni, West Africa. Relative abundance and reproduction activities of these pteropids are concordant with seasonal rainfall and availability of foods in Rio Muni. There are major differences between these sympatric species with regard to roosting sites, foods and feeding behaviour, levels of flight, and aerodynamic properties. Thermal responses vary between the species and are correlated with differences in behavioural thermoregulation.

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1972.tb03118.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

The larval speciesAtlantocaris gigasOrtmann is shown to be conspecific withHeterocarpus ensiferA. Milne Edwards, whileProcletes biangulatusBate is the larva ofHeterocarpus levicarina(Bate). Each species passes through 13–15 zoeal stages and 3–4 megalopal stages. The later zoeal stages are large, have a long toothed rostrum, a carinated carapace and dorsal abdominal spines. The carinae on the carapace are retained in the adult; the rostrum becomes shortened and the abdominal spines modified at metamorphosis. Larval characters support the retention ofHeterocarpusin the Pandalidae.New information on the distribution of both species is inclu

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1972.tb03119.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY