摘要:

The cytochemical nature of the secretory contents of the unicellular glands—the mucous cells and the sacciform granulated cells in the epidermis ofMonopterus cuchiahas been described in order to understand their physiological significance.The mucous cells secrete mainly the acid mucopolysaccharides and mucoproteins in addition to small amounts of phospholipids. The secretory contents of the sacciform granulated cells are proteinaceous in nature and give strong reactions for elastin, tryptophan and tryosine. High amounts of cholesterol and small amounts of phospholipids and acid mucopolysaccharides are also identified in these sacciform granulated cells.Phospholipids, mucoproteins and elastin could well increase the viscosity of mucopolysaccharides retaining the slimy secretions on the surface for relatively longer periods. The retention of mucopolysaccharides and elastin on the surface for longer periods that can bind large amounts of water has been correlated to keep the skin moist, facilitating the cutaneous respiration and preventing the fish from desiccation when it is on land. The role of elastin in protecting the fish from various chemical attacks and mechanical stresses is also discussed.Tryptophan secreted by sacciform granulated cells may have the immunological role facilitating the antibody transfer across the epidermi

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1977.tb04160.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Two new species ofChonopeltis(Crustacea: Branchiura), parasitic on cyprinid fishes, are described from rivers in the extreme S.W. Cape region of Africa. These emphasize the remarkable nature of the fauna of these rivers, which includes several endemic fishes. Like their hosts these closely related parasites came from the north and have close affinity with a species from the Orange River system. Their probable evolutionary history is discussed. Keys to both sexes of all described species ofChonopeltisare given.

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1977.tb04161.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

A study is made of the histology, distribution and ultrastructure of nerve‐organs in the carpal and ventral sinus hairs of the squirrelSciurus vulgarisL. These sinus hairs were found to be typical tactile hairs. Their situation on the inner surfaces of the forelimbs, and on the ventral body wall is assumed to be useful during climbing. Five different types of nerve end‐organs were found:1. Ring‐shaped end‐organs, especially in the ring sinus, associated with certain cells in connectivetissue and in many cases also anchored to the hair follicle.2. Merkelcells in the basal cell layer of the outer root sheath at the level of the ring sinus.3. Lanceolate end‐organs between the glassy membrane and the connective tissue of the ringwulst and betweenthese in the upper part of the ring sinus.4. Encapsulated end‐organs in the cavernous sinus.5. Free thin n

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1977.tb04162.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

An account is given of the various movements of the proboscis of Bonellia viridis. When at rest, the proboscis is coiled up in front of the trunk. The proboscis lobes progress with a velocity of the order of 1 mm/sec by means of powerful cilia situated on the dorsal surface of the leading edge. The lobes passively drag and uncoil the stem of the proboscis which is further uncoiled by muscular contractions taking place along the uncoiled part of the stem. Proboscis retraction takes place by means of contraction of the numerous longitudinal muscle strands of the stem. The terminal lobes can attach to the substrate and pull the trunk by contraction of the proboscis stem. The proboscis often ties itself into a knot which it can untie.

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1977.tb04163.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Trunk irrigatory and locomotory movements in the echiuranBonellia viridisconsistofperistaltic waves of constriction. Irrigation is by antero‐posterior waves. Locomotion in the burrow may be produced in three different ways: (a) by antikinetic, (b) by synkinetic, and (c) by antikinetic and synkinetic waves in strict alternation. The animal can turn in the burrow and pass out of narrow holes. The animal can move by peristaltic waves also outside its burrow. The versatility of locomotory modes is related to its inhabiting ready‐made burr

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1977.tb04164.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

The veliger larva of Hydrobiu ulvue (Pennant) from the west coast of Wales is described and illustrated from veligers hatched in the laboratory and collected in plankton samples. The larvae are planktotrophic and it is estimated that the pelagic phase is of about four weeks duration. In terms of density they form an important constituent of the plankton of inshore waters. The veliger larva ofLittorinalittoreu (L.) is also described and illustrated, and it is suggested that some of the conflicting reports on the length of the pelagic phase ofH.ulvae result from confusion in indentification of the larvae of these two species.

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1977.tb04165.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Two new anuran suborders, based on two states of the trigeminofacial ganglion character complex are proposed. A subsidiary character is the presence or absence of free ribs in extant taxa. These new suborders are more clades (sister groups) than sequential levels of organization. Discoglossoidei, retaining separate trigeminal and facial ganglia and free ribs, encompasses only Leiopelmatidae and Discoglossidae, although by definition it would include the common ancestor of both lineages. Ranoidei have the trigeminal and facial ganglia fused and extant taxa lack free ribs. This group includes all other frogs.Only the superfamiliesPelobatoidea and Pipoidea are reallocated by the new arrangement. The former are now regarded as representing the ranoidean stem group. Both laival and adult morphology show that pipoids are highly derived rather than primitive frogs, and their trigeminofacial systems show that they are ranoideans rather than discoglossoideans. They presumably are ultimately derived from pelobatoids, but the known taxa are too specialized for direct derivation and there must have been an intermediate group with pipoid tadpoles but without extreme specializations for either fossorial or aquatic life.

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1977.tb04166.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

The spatial and social organization of a winter communal roost of Rooks (Corvus frugilegusL.) was examined. The behaviour of rooks in the roost was found to reduce the rate of loss of heat energy for all or some of the population. The saving of energy experienced by young birds by roosting in sheltered positions was important because of the smaller energy reserves available. When the weather became exceptionally severe, dominant individuals, in seeking sheltered positions, forced less dominant birds from more sheltered to far less sheltered positions, thereby increasing their energy loss. The effects of this selectively‐acting social hierarchy during the night is exacerbated on the feeding grounds during the day when some rooks starve especially those low in the hierarchy. The daytime feeding situation will also increase the lower critical metabolic temperature of the young rooks by lowering the nutritional plane. Other evidence is presented to show that in winter, mortality of young rooks is higher than that of adult rooks.It is argued that the change in the spatial organization in the roost induced by weather and determined by a selectively‐actingsocial hierarchy operates to reduce the rate of energy loss of the majority of the rooks while the remainder suffer an increasing energy defi

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1977.tb04167.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

A total of 317 steps of walking Silver gulls (Larus novaehollandiiae) and filmed sequences of 24 other species of medium‐sized and large birds were analyzed. The angles made by the tibiotarsus‐tarsometatarsus joint of each leg during walking were measured. These varied depending on the species. In the Silver gull, where the angles were correlated with speed, the leg bent more sharply the slower the step; otherwise the angles were not correlated with speed. In all but the four largest birds, as in man, the leg was more bent in the middle of its stance phase than it was at the beginning or end of this phase. Thejoint was never completely straight, or 180″. In general the larger the bird, the slower was its step. The Silver gull and other birds do not bob their heads back‐and‐forth as they walk, but many birds do. It is not known why some birds bob their heads, although it may be correlated in part with a relative horizontal body posture, with seeing effectively, with balance during locomotion, or with habitat. The Silver gull does not hop, but some birds do, usually birds that live in the bush, or that

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1977.tb04168.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Observations on the narial excrescence of the gharial are reviewed, with special reference to the size and sex of animals in which it occurs. Its morphology in two adult specimens is described; its functional anatomy and mode of development are reconstructed and its probable functions are discussed. Some observations on the pterygoid bulla are also made.

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1977.tb04169.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY