摘要:

The characters linkingMiroungaandCystophorain the subfamily Cystophorinae are the reduction of the incisors to3/1, the nasal sac of the male, and also the general similarity in shape of the postcanine teeth. Because of the unreliability of dental characters, and the possibility of convergence producing the nasal sac, the entire skeleton and some soft parts of the body have been considered. This examination has produced 17 good characters in whichCystophoraagrees with other northern phocids, andMiroungawith other southern phocids. Other characters confirming this division, but not considered trenchant enough for inclusion in the table, have also been found.It is suggested that the subfamily name Cystophorinae be abandoned. The family Phocidae is therefore divisible into two subfamilies;Cystophorabeing included in the Phocinae, andMiroungain the Monachinae.Certain characters suggest thatErignathusandMonachusmay be the forms linking the typically northern and the typically southern phocids.

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1966.tb02958.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

Graniais a genus of Enchytraeidae which was erected to contain a single Irish marine species. The re‐examination of the type material of this species and the discovery of some new American material has made possible the revision of the earlier description and the erection of a new species. A third species, formerly located inEnchytraeus, is now recognized as belonging inGrania.As a result of these investigations the genus has been re‐defi

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1966.tb02959.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

The White Amur or Grass carp,Ctenopharyngodon idellaVal. is almost exclusively herbivorous, feeding chiefly on macrophyte material. The pharyngeal teeth are described, and their effect on the ingested food material. The distribution of the digestive enzymes along the gut suggests that most amylase and protease is in the mid‐gut, and lipase in the anterior gut. The gut is short for a herbivore, and food passes through in less than eight hours at 28°c to 30°C. Digestion is incomplete, and about half the food material is passed out as faeces which can support, directly or indirectly, a large biomass of other species of f

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1966.tb02960.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

The “hairs” and various types of sensilla present on the mouth parts ofSchistocerca gregariaare described. The distribution of the sensilla on the clypeo‐labrum, labium and theHmaxillae has been plotted in detail, and the general distribution of all types of sensilla on each of the mouth parts is described.A comparison is made between the distribution of certain sensilla on the clypeo‐labrum in first instars and adults.The probable role of the sensilla in feeding is di

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1966.tb02961.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

The blood capillary system ofTubifex tubifexhas been investigated using various methods of killing and fixation. When the worm was killed slowly and in a relaxed state capillary systems to both the intestine and the body wall showed clearly and have been described.

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1966.tb02962.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

A detailed description is given of the anatomy of the head, thorax, proboscis apparatus and pygidium of the maldanid polychaetesClymenella torquata(Leidy) andEuclymene oerstedi(Claparède) (=Caesicirrus neglectusArwidsson, 1911). The head consists of prostomium, peristomial region and one achaetous segment which is undoubtedly a metamere. Whether the peristomium should be counted as another rests on the definition of a metamere, about which opinions differ. Evidence is presented which suggests that each of the two paired groups of proboscideal retractors is derived from a head septum.Probably because of the relatively large size of the proboscis, not only the head, but also the first four chaetigers (= thorax) act as a pump to effect the eversion of the proboscis by coelomic fluid pressure. The thoracic septa are highly specialized in relation to this function. In both gross and detailed anatomy, and in mode of functioning of the region, the maldanids show many resemblances to some arenicolids.The pygidium consists of a ring‐shaped thickening (the callus ring), the anal funnel and the anal cone.Based on this investigation of anatomy, a system of description is suggested which aims to avoid ambiguity and to eliminate from future maldanid literature the type of confusion which exists in it at prese

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1966.tb02963.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

The present study ofClarias senegalensisC.&V., from a small man‐made lake in the coastal savanna of Ghana, was initiated because this species has not been investigated previously and there is a need to have precise information regarding its general biology and food niche both from the theoretical and practical viewpoints. This catfish becomes sexually mature when about 32 cm in length and once a year, after the onset of the major rains in April, or early May, they ascend the feeder stream to spawn in its flood zone. Spent fish soon return to the lake after spawning but smaller immature fish do not do so until September. As with other piscivorous fish the feeding intensity is low and with one exception the stomachs of the monthly samples were on the average less than half full. The suggestion of a slight seasonal increase in the amount of food consumed from August onwards appears to be correlated with a seasonal increase in standing crop and is followed later by an increase in condition factor.C. senegalensisis extremely euryphagous but it subsists mainly on organisms swimming in midwater including fish such asTilapia, zooplankton and insects, those living on the surface of the sediment and small organisms swimming near the surface of the sediment. Animals from these habitats have a higher forage ratio than those living under stones, in the sediment or in shallow water or in vegetation close to the shore. Vegetation, adventitious food and detritus are of little consequence toC. senegalensisin Nungua lake and it is suggested that the latter is not exploited because the sediments are poor in organic matter. The euryphagous habits ofC. senegalensisare shared by otherClariasspecies and this is reflected in several anatomical adaptations concerned with feeding. Seasonal changes in the dietaries are very slight because the catfish do not exploit phytophilous species to any great extent even when they become abundant during the wet season. For this reason it is doubtful whether they are of value in controlling important vectors of diseases many of which are phytophilous. Although there is a suggestion that larger fish eat more vegetation, phytophilous species and adventitious food the evidence for ontogenetic changes in the deitaries are very slight and fish in all the size groups eat minute food organisms such as copepods and also large ones such as fish includingTilapia.The possibility of combiningClariaswithTilapiain fish ponds is, therefore, worthy of consideration. The factors which cause expansion and contraction of food niches are discusse

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1966.tb02964.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

The diet of two intertidal species of gammarid,Marinogammarus obtusatusDahl andM. pirlotiSexton and Spooner is described. Both species feed largely, but not exclusively, on decaying algae, but may eat some living algae and, more rarely, carrion.Their feeding activities are influenced by the rhythmic pattern of tidal ebb and flow, feeding only when covered by water. When immersed by the incoming tide they ingest food rapidly for a while and then feed more intermittently, ingesting small amounts at a time until they are uncovered once more by the receding tide. They probably eat sufficient food to fill the gut twice in 24 hours. The optimum rate for the digestion of food is approximately five hours, although food remains in the gut for about 12 hours.The pH of the contents of the proventriculus, digestive gland and intestine ofM. obtusatusis distinctly acid. Digestive enzymes are secreted only by the digestive gland. Carbohydrases are present which will hydrolyse soluble starch, glycogen, sucrose, maltose, arbutin, salicin, raffinose and melibiose. Inulin, lactose and cellulose are not hydrolysed. Non‐specific esterase and true lipase were detected by histochemical methods.It is concluded that the food supply available to these animals is plentiful and it is unnecessary to utilize the food supply to the maximu

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1966.tb02965.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

Very little comparative study has been made of the distribution of pigments within the structure of the egg‐shell. The present paper is a general account of the distribution of the pigments within the thickness of the egg‐shells of the different avian genera, and was undertaken in order to assess the value of this character for taxonomic purposes. Egg‐shells tend to cleave along a radial plane and the radial surfaces of shell fragments were examined under a microscope and the distribution of colours noted.Only two pigments are known to be present in most eggs, a blue biliverdin and a protoporphyrin responsible for reds, browns, blacks and yellows. The distribution of colours as it appears in fragments of egg‐shells of the different avian families is described, those of the Passeriformes being discussed as a single group. In general, the shells appear white or blue, with other pigment present either as a thin superficial layer, or in small patches scattered at intervals through the thickness of the shell. In 11 genera, various pigments were found to be present through a significant portion of the outer shell structure; from one‐third to one‐half the total thickness. There did not appear to be any common factor underlying this occurrence.The only major variation in distribution was found in patterned eggs, some of which had all the pigment producing the pattern limited to the surface layer of the shell, while in others this was present at varying depths within the thickness of the shell. The former type was found in eight families only, and in three of these, Falconidae, Opisthocomidae and Jacanidae, was limited to one family in an order containing numerous families.Fugitive pigments occur in some shells. An unstable porphyrin gives a pink flush only seen in very fresh eggs. In a few species the fresh eggs are green but subsequently become blue. The green colour appears to be due to a combination of blue biliverdin and a yellow pigment, possibly bilirubin.In view of the general similarity of pigment distribution in most egg‐shells this character would appear to have limited use in taxonomy, but the difference in distribution of pattern pigments might be of some

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1966.tb02966.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

Four species of polydesmoid Diplopoda collected by Mr L. D. E. F. Vesey‐Fitzgerald, from the Pacaraima Mountains, British Guiana are described:Mestosoma hylaeicumJeekel,Iphyria macconnelli(Pocock),Leptherpum jeekelisp. nov. and a new genus and species of Chytodesmid,Adenomeropus fitzgeratdi. Arevised keyto Leptherpumis given includingL. jeekeliand a new combination,L. schomburgki

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1966.tb02967.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY