bluuebunny/crossref_metadata_2025_split huggingface dataset:
Blood cell formation in the River lamprey, Lampetra fluviatilis
Authors: Percy Lord Richard , Potter I. C. 
Published: August 2009

Haemopoiesis has been studied throughout the life cycle of the parasitic lamprey, Lumpetra fluviatilis, with supplementary data being provided by its nonparasitic derivative, Lampetra planeri. Attention was paid to the location of the principal haemopoietic sites in both the larval and post‐larval stages and to the mode of differentiation of the blood cells. In the prolarva, the formation of blood cells takes place initially in the blood islands but, at the time when the gut starts to rotate, this role is taken over by the typhlosole. After the ammocoete has reached about 20 mm in length, division and maturation of blood cells were also clearly detected in the intertubular and fat cell region of the nephric fold. Both the typhlosole and nephric fold discharge blood cells into the circulation and throughout the rest of larval life constitute the main sites of lymphopoiesis, erythropoiesis and granulopoiesis. At the beginning of transformation, however, both these structures undergo involution and by the end of metamorphosis the haemopoietic function has been assumed by the fat column. This latter organ remains active throughout the adult phase until near the end of the spawning run at which time it undergoes massive degenerative changes.Differentiation of blood cells from the fixed cells of haemopoietic tissues occurs only in the blood islands of the prolarva and in the typhlosole during the very earliest stages of its development. Throughout the rest of the life cycle, the mode of formation of blood cells was the same in haemopoietic tissues containing a reticular network (typhlosole, fat cell region of the nephric fold and fat column) as in haemopoietic tissue where there was no such fibrous arrangement (the intertubular tissue of the more ventral regions of the opisthonephric kidney). Haemopoietic tissues could be seen to be formed in all the above structures by the accumulation of immature cells in tissue spaces which form a suitable environment for cell division and maturation. Descriptions are given of lineages leading from small lymphocyte‐like stem cells to erythrocytes and to eosinophilic and neutrophilic granulocytes, and from large lymphocytes to macrophages.
Underwater predatory behaviour of the American mink (Mustela vison)
Authors: Poole Trevor B. , Dunstone Nigel 
Published: August 2009

Fishing behaviour of the American mink (Mustela vison Schreber) was investigated in the laboratory. Data were recorded using ciné film and tape recorded commentaries. Three species of prey were presented to mink, namely, carp (Cyprinus curpio), goldfish (Carassius auratus) and minnows (Phoxinus phoxinus).It was found to be necessary to train ranch‐bred mink to enter water and catch fish; young mink appeared to be easier to train than adults. Mink spent 5–20 sec under water when fishing; prey had usually previously been located from an aerial vantage point. Predatory behaviour was highly organized sequentially whereas fish were more prone to indulge in unpredictable stratagems; the behaviour of mink and fish were highly correlated.The mink's efficiency in catching fish was related to prey size (smaller individuals being more vulnerable to capture) and shoaling. Minnows, which form highly organized shoals, were less easily caught when present in large numbers; this was not true of a loosely shoaling species, the carp.Of the three species of prey presented, vulnerability to capture took the form goldfish> carp> minnow; these differences, however, may have been influenced by the fish's previous experience of underwater predators.
Behavioural adaptations of the Jackass penguin, Spheniscus demersus to a hot, arid environment
Authors: Frost P. G. H. , Siegfried W. R. , Burger A. E. 
Published: August 2009

Penguins tend to be overinsulated for life on land. A study of the Jackass penguin Spheniscus demersus was undertaken to investigate the behavioural adaptations that enable the species to cope with the exigencies of a hot, terrestrial environment.The Jackass penguin is mainly crepuscular and nocturnal at its breeding stations. The numbers of birds present on land are highest at night and lowest during the day. The majority of birds leaving a breeding colony do so just after dawn. Birds begin to return to the colony during the late afternoon. The frequency of displays is highest at dawn and from dusk to midnight. This activity cycle enables birds not engaged in incubation or chick guarding to avoid conditions promoting heat stress.Birds remaining in the colony during the day employ strategies such as burrow‐nesting, body‐orientation and evaporative cooling to reduce the effects of high insolation. Compared to the ambient, the microclimate of burrows is more constant; relative humidity is higher; air temperatures fluctuate less; and wind effect is negligible. Most important, birds nesting in burrows are protected from direct insolation. Egg and nest‐air temperature in a burrow are relatively constant. Burrows facing east are cooler than those facing west. However this does not influence burrow‐orientation, which is determined by the slope of the ground.Birds exposed to high insolation orientate with their backs to the sun. The lightly feathered areas of the body are shaded. This facilitates heat loss by convection and re‐radiation from these shaded surfaces. In this position dorsal surface temperature regularly exceeds body temperature. It is suggested that heat gain from the dorsal surface is restricted by efficient insulation, primarily an adaptation to the aquatic environment. On overcast days orientation is non‐directional. In the early morning when ambient temperatures are relatively low, the birds also orientate with their backs to the sun. This is interpreted as sunbathing.Body temperatures were significantly higher on a hot than on a cool day. The Jackass penguin appears to be relatively thermolabile. This would facilitate both energy conservation in water and resistance to heat stress on land. The overall thermoregulatory strategies of the Jackass penguin for life in two different environments are discussed.
The effects of exposure and predation on the shell of two British winkles
Authors: Heller Joseph 
Published: August 2009

Changes in shell size and shell shape of the two British winkles Littorina nigrolineata and L. rudis were studied in relation to exposure and to crab‐size. In both species, shells from exposed shores are smaller and more globose than those from sheltered shores. Also, in rudis of exposed shores the mouth is relatively wider. In shores of equally sheltered conditions, shells are bigger at those localities where crabs are large than at those localities where they are small. The largest shells are found in those localities where it is extremely sheltered, and the crabs are very large.It is argued that on exposed shores, small shells are favoured because they have more possibilities than large ones to shelter in crevices and in barnacle interspaces, from the impact of winds and waves. A globose shell could accommodate more foot muscle and thus enable a stronger adherence to the rock; and an increased mouth diameter would increase the area of foot adherence to the rock. On sheltered shores, on the other hand, large, narrow‐mouthed shells are favoured because they discourage crab predation, large crabs being abundant mainly on sheltered shores.The possible significance of shell size and shape in relation to zonation is discussed, in view of the different predatory and physical conditions which prevail in different zones of the shore, and the different shell specializations which these conditions would require.
An investigation of individual, age and sexual differences in the play of Rattus norvegicus (Mammalia: Rodentia)
Authors: Poole Trevor B. , Fish Jane 
Published: August 2009

Eight litters of Rattus norvegicus of the PVG/C hooded strain were observed in order to investigate the roles of individuality, sexuality and age in playful behaviour.Three measures of social play, namely, initiations, numbers of play bouts and numbers of playful elements performed were all found to be positively correlated. The incidence of social and solitary play were also positively correlated so that a concept of “playfulness” appeared to be justifiable. Playfulness showed no correlation with the general level of non‐playful locomotor activity.Male rats were more playful than females but only minor sex‐related differences were found to occur in the sequential organisation of play.Older rats showed longer play bouts and a higher degree of temporal organisation. Considerable individual differences in playfulness were recorded and in single sex litters playful rats were found to play together.The majority of opponents, in playfighting, alternated between the roles of attacker and defender.
A remarkable pyloric caecum in the evermannellid genus Coccorella with notes on gut structure and function in alepisauroid fishes (Pisces, Myctophiformes)
Authors: Wassersug R. J. , Johnson R. K. 
Published: August 2009

Gross morphology and development of the gut in the circumtropical genus Coccorella Roule (Alepisauroidei, Evermannellidae; two species C. atrata (Alcock, 1893) and C. atlantica (Parr, 1928)) is described and the gut structure of this genus is compared with that of other alepisauroid and myctophoid fishes. Alepisauroids characteristically have an enormous sac‐shaped stomach and a simple, straight intestine. It appears that this gut morphology is a specialization for the ingestion of very large food particles and is an adaptation to the food‐limited midwater environment. Coccorella is remarkable in having a medial pyloric (intestinal) appendage that extends forward from the ventroanterior margin of the intestine, passes between the cleithra, beneath the heart, dorsal to the isthmian musculature, and ends blindly beneath the first basibranchial. This caecum is surrounded by the darkly pigmented peritoneal lining of the coelomic cavity and is easily visible in the floor of the orobranchial cavity. The caecum can be seen in the smallest available larva (6.3 mm SL) but does not develop its complete cephalic extension until the larvae are 20 to 25 mm SL.Portions of the alimentary tract in Coccorella were examined with light and scanning electron microscopy. No substantial histological differences between caecum and intestine have been found. It is hypothesized that the caecum in Coccorella has a function similar to that proposed for pyloric caeca in other fishes, viz. to increase the resportive and storage capacity of the intestine.Although pyloric caeca vary enormously in size, number and morphology among teleosts, Coccorella is the only genus known with any appendage of the alimentary tract extending into the head. General hypotheses on the adaptive significance of pyloric caeca are reviewed but none satisfactorily explain the appearance of this unique neomorphous feature in Coccorella.
A comparison of relative growth in Cerastoderma (=Cardium) edule, Modiolus modiolus, and Mytilus edulis (Mollusca: Bivalvia)
Authors: Brown R. A. , Seed R. , O'Connor R. J. 
Published: August 2009

Relative growth has been studied in intertidal populations of Cerastoderma edule and Mytilus edulis and in a subtidal population of Modiolus modiolus. Size dimensions were generally more variable and shell thickness generally greater in the intertidal species. Total weight was correlated with shell weight in all three species but there was a progressively greater emphasis on tissue growth through the sequence Cerastoderma, Mytilus, Modiolus. These results are interpreted in terms of differences in stability between their respective habitats.Analyses of individual year classes in Cerastoderma showed a marked pattern of alternating years of good and poor growth.
Waterfowl feather proteins: analysis of use in taxonomic studies
Authors: Brush Alan H. 
Published: August 2009

S‐carboxy keratins from waterfowl feather were prepared and studied in regard to effect of preparation, individual and intraspecific variation. These results were then expanded in in an extensive intraordinal study of the waterfowl using polyacrylamide gel electrophoresis (PAGE) to compare representatives of approximately 40 genera in regard to intra‐ and intertribal variation. The PAGE was supplemented by double diffusion and immunoelectrophoresis using antisera to SCM—keratins of Anas. The resultant patterns, especially in PAGE were useful in testing a number of taxonomic hypotheses and demonstrated the conservative nature of these proteins. The basic ordinal structure of the waterfowl was supported but specific questions, especially to the relations of a number of monotypic or intermediate genera and a proposal regarding the sea ducks, were addressed. In almost all cases the placement of such taxa were resolved.The PAGE data were used to test a number of published proposed phylogenies of the waterfowl.SCM‐keratins of feathers are a complex of similar sized monomers with great immunological similarity. The data presented here are discussed in regard to waterfowl systematics and the use of electrophoretic data to test systematic theory.
Biochemical and morphological observations on the wallaroos (Macropodidae: Marsupialia) with a suggested new taxonomy
Authors: Richardson B. J. , Sharman G. B. 
Published: August 2009

Two discriminant functions were designed using skull measurements, one to discriminate Antilopine wallaroos (antilopinus form) and Euros (erubescens form) and one to discriminate Euros and Black wallaroos (bernardus form). These three forms separated into different areas of a scatter‐gram using the two discriminant functions as axes. Skull data from wallaroos not attributable to these forms fitted into the erubescens portion of the scattergram.Northern wallaroos (alligatoris form), which were indistinguishable from wallaroos from southern Australia on skull data, are sympatric with Antilopine and Black wallaroos in Arnhem Land. Here Antilopine and Northern wallaroos had different gene frequencies for three of the four blood proteins studied; Northern wallaroos being most like Euros and wallaroos elsewhere. The Black wallaroo, which is confined to Arnhem Land and is morphologically quite distinctive, had a different haemoglobin type to that of all other animals studied.On the basis of the morphological and biochemical data presented, the wallaroos can be divided into three species—Macropus (Osphranter) antilopinus (Gould, 1842), the Antilopine wallaroo; Macropus (Osphranter) bernardus Rothschild, 1904, the Black wallaroo and Macropus (Osphranter) robustus Gould, 1841. M. robustus is divisible into four subspecies—M. robustus robustus the Eastern wallaroo; M. r. erubescens, the Euro; M. r. woodwardi, the Northern wallaroo and M. r. isabellinus, the Barrow Island wallaroo.
The articular surface of the temporal bone in certain fossil hominoids
Authors: Ashton E. H. , Flinn R. M. , Moore W. J. 
Published: August 2009

Although quantitative variations exist between living Man (Homo sapiens sapiens) and the extant great apes (Pongo, Pan, Gorilla) in such features of the articular surface of the temporal bone (a part of the temporomandibular joint) as the proportionate development of the postglenoid tubercle, the relative prominence of the articular tubercle and the slope of its posterior face, these do not individually effect a clear differentiation between the four extant genera. But in multivariate combination of these features, although Pan and Pongo are relatively closely associated, Gorilla and Homo sapiens sapiens are distinct, and also clearly differentiated from each other. The differences between genera of extant apes are, on average, as great as those between extant Man and individual apes.As portrayed by such multivariate compound, this anatomical region in four fossil groups displays a unique configuration differentiating Homo sapiens neanderthalensis, Homo erectus pekinensis, Australopithecus africanus and Australopithecus robustus both from one another and from extant types. The differences are such that the fossil species lie uniquely and not intermediate between extant groups.Definable age changes in this multivariate compound occur in both Man and apes but neither these, nor overall differences between adults, appear to be associated with marked contrasts in the pattern of jaw movement. It would thus seem improbable that inferences can be made from these features about the type of jaw movement that characterized the several fossil groups.
Protein and carbohydrate histochemistry in relation to the keratinization in the epidermis of Barbus sophor (Cyprinidae, Pisces)
Authors: Mittal A. K. , Agarwal S. K. , Banerjee T. K. 
Published: August 2009

The distribution of protein and carbohydrate constituents in the epidermis of Barbus sophor is described in order to give a better understanding of its cellular organization and physiology.Various cytochemical techniques show the keratinized nature of the outer free margins of the polygonal cells in the most‐superficial layer. These contain appreciable amounts of cysteine bound sulphydryl groups, basic proteins, protein bound NH2 groups, ribonucleic acid and calcium and give a strong Papanicolaou's reaction. Absence of cystine bound disulphide groups suggests that the cornified layer in B. sophor is probably mechanically weak as adjacent keratin chains remain unbonded. The polygonal cells showing keratinization at the outer free margins remain metabolically active and are not sloughed off at the surface. This is in contrast to the keratinized epidermis of other teleosts so far reported in which the keratinized cells are dead and are sloughed off at the surface.In addition to keratinization the polygonal cells undergo mucogenesis synthesizing sulphated acid mucopolysaccharides.The presence of eosinophilic granular cells in the epidermis is interesting. The possible role of these cells in the protection of the epidermis has been discussed. The epidermis on the inner surface of the scale is very thin so it may not have much protective significance in these areas.
The biology of the Bush rat, Aethomys hindei Thomas in Southern Uganda
Authors: Okia Nathan O. 
Published: August 2009

Studies were made on the Bush rat, Aethomys hindei in Lunyo forest (0° 5', 32° E) on the Northern shores of Lake Victoria. Rats were trapped daily (Monday‐Saturday) for 47 weeks during November 1970 to November 1972 from 20–49 live traps set in a 40 by 100 m grid. In the laboratory they were examined for the condition of the external genitalia and for signs of pregnancy. Some pregnant rats were kept in the laboratory and their progeny measured at weekly intervals. The rate of growth (weight gain in g per day) was determined for both laboratory and field rats. Growth curves of laboratory rats were used to calculate the ages of young (<100 g) field rats, even though the results showed that at between 50 to 100 g field rats grew faster than laboratory rats and between 100 to 150 g, laboratory rats grew faster than field rats.The weight distribution of rats in the field showed a clear weight difference between males and females; with some males weighing as much as 171 g while the maximum weight recorded for females was only 146 g. The weights obtained extend the weight range of these rats beyond that previously published.Breeding (pregnancies) in the field occurred mostly in the wetter months of November‐ December and April whereas young animals occurred more in the drier months of December and January. Births obtained by calculation from laboratory growth curves occurred more in November.Seasonality in the intensity of breeding was indicated although monthly breeding throughout the year was observed. The months of highest population densities were December, January and April.
Studies on the anatomy, life history and behaviour of Marsupiobdella Africana (Hirudinea: Glossiphoniidae)
Authors: Lande Virginia M. van der , Tinsley R. C. 
Published: August 2009

All glossiphoniids afford some degree of protection to both eggs and young but Marsupiobdella africana is unique in that it develops a permanent brood pouch on the ventral surface. Developmental and histological studies show that the marsupium is epidermal in origin. The pouch rudiment forms as a shallow groove before the eggs leave the ovisac and, when functional, the pouch becomes enormously distended reaching from oesophagus to anus and considerably compressing the internal organs. Its opening is a narrow sphinctered pore which apparently permits some degree of parental control over the release of the brood.The course of the life history has been established from natural and experimental infestations of M. africana on the Clawed toad, Xenopus laevis laevis, from the Cape, South Africa. The leeches develop to maturity over a period of two to three weeks (at 22°C) whilst attached to the host, but copulate only after detachment. Present evidence suggests that the embryos are transferred externally from female gonopore to the pouch within which up to 50 young are brooded for about four weeks. The juveniles are relatively well developed at the time of their release; they can be carried in the pouch at an infective stage for up to two months and when contact with X. laevis is made they are discharged explosively. Each leech reproduces once, dying after a maximum life span of about four months. Other Xenopus toads (X. laevis victorianus and X. vestitus), were successful hosts in specificity tests, but Rana and Bufo species were not infected, nor were tadpoles of Xenopus. Marsupiobdella has a number of unusual anatomical features in addition to the brood pouch. The oesophageal organ is described in some detail; its cells are either glands or mycetocytes. The forward displacement of the anus cannot be explained on either functional or phylogenetic grounds. The presence of the velum is unique amongst glossiphoniids and probably the most significant peculiarity in that it affords evidence for the phylogeny of the group.
The statocyst of Vampyroteuthis infernalis (Mollusca: Cephalopoda)
Authors: Stephens P. R. , Young J. Z. 
Published: August 2009

The statocyst shows a remarkable combination of features of decapods and octopods confirming that Vampyroteuthis is a relic somewhere near the ancestor of both groups. The lining of the statocyst separates from the outer wall, forming an inner sac, filled with endolymph, surrounded by perilymph. This is the condition found in octopods, never in decapods. The macula is partly divided into a macula princeps and macula neglecta, as in decapods but never in octopods. There are numerous statoconia, but no large statolith has been seen. The crista has four parts as in decapods, but they are not sharply separated. There are numerous small anticristae, with the general form found in decapods, differentiated into pegs and hooks.The wall of the inner sac contains numerous hair cells. These hairs protrude between the epithelial cells. The bases of the cells are drawn out into fine processes, presumably some dendritic and some axonal. There is thus a plexus of nerve fibres all over the wall, communicating with the crista nerve.There is a very large posterior sac of unknown function, lying behind the crista. It contains only one large anticrista and the opening of Kölliker's canal, which is very large.