bluuebunny/crossref_metadata_2025_split huggingface dataset:
The muscles of newly hatched Schistocerca gregaria larvae and their possible functions in hatching, digging and ecdysial movements (Insecta: Acrididae)
Authors: Bernays E. A. 
Published: August 2009

A detailed study of the hatchling musculature in Schistocerca gregaria (Forskål), and comparison with muscles of older first‐instar larvae and adults, revealed four categories of muscles: those which are present throughout life (permanent muscles), those which are present only in the hatchling and which break down during the first‐instar larval stage (first accessory muscles), those which are characteristic of larvae and break down in the adult (secondary accessory muscles), and those which are rudimentary or absent to start with, becoming functional in the adult. This last group, including the flight muscles and the muscles of the genitalia have not been studied. Of the remainder, the head and legs contain only permanent muscles, the contrast between larvae and adults being in the neck, thorax and abdomen. The positions and possible functions of the two groups of accessory muscles are discussed, particularly in relation to hatching, digging and ecdysis of the vermiform larva, and specific functions of the permanent muscles of neck, thorax and abdomen at this time are suggested, and compared with their better known functions in the fully hardened, free‐living insect.Summary:The study of the musculature of the newly hatched locust revealed not just the normal complement of muscles found in the adult, but batteries of accessory muscles which aid hatching, digging and ecdysial processes. Some of these muscles are attached across and onto the membranous regions and probably prevent ballooning of the intersegmental regions during high pressures, thus ensuring expansion of the presumptive sclerite regions rather than a separation of them.In the abdomen the lack of apodemes, the small overlap of adjacent sclerite regions and the easily distorted cuticle are all factors allowing the external muscles to assist the internal muscles and the accessory muscles in abdominal contraction. Such contractions are required for hatching and digging of the vermiform larva.Special muscles are associated with the ampullae and brustia, which break down during the first instar, while the other accessory muscles persist until the adult stage is reached, and are presumably used at later ecdyses.
The structure of the female reproductive system in the Eurytomidae (Chalcidoidea: Hymenoptera)
Authors: Copland M. J. W. , King P. E. 
Published: August 2009

An account is given of the structure of the gaster and mechanism of the ovipositor in the females of the Eurytomidae. The histology and the possible functions of the components of the reproductive systems are described and its bearing on their phylogenetic relationships of the group discussed.Summary:The female gastral sclerites and ovipositor mechanism in the Eurytomidae have a number of distinctive characters. Within the family there is a progressive evolution of a coiling of the ovipositor associated with accommodating a longer shaft within the abdomen. Each ovary has three ovarioles and the shape of the egg is constant. There are two pairs of colleteral glands, a well developed “venom” system and a distinctive spermatheca.The family has affinities with the Torymidae and may be close to the ancestral chalcid stock.
The mammary glands of the Red kangaroo with observations on the fatty acid components of the milk triglycerides
Authors: Griffiths Mervyn , McIntosh D. L. , Leckie R. M. C. 
Published: August 2009

The structures and physiology of the mammary glands of the lactating Red kangaroo are the most complex to be found in the class Mammalia. The female Red kangaroo can exhibit, simultaneously, two glands regressing from the tubular condition found at birth, one gland growing and differentiating from the tubular to an alveolar condition supporting a small pouch young, and a fourth in a state of full lactation supplying a young at heel. As lactation proceeds the two regressing glands become quiescent and then later re‐differentiate to the oestrus or birth condition independently of the lactating glands.As well as differing anatomically the two lactating glands are very different biochemically; the milk for the sustenance of the pouch young contains a large amount of palmitic and relatively little oleic acid whereas the gland supplying the young at heel secretes a milk with little palmitic and much oleic acid.Summary:The amount of crude lipid in the milk of the Red kangaroo sampled from day 1–4 day to day 360 of lactation tends to increase. The fatty acid complement of the milk fat taken day 1–4 to the 72nd day differed greatly from that taken at 100–360 days. The early milk triglycerides contained on the average 44·2% palmitic acid and 24·1% oleic, whereas in mature milks the proportions were reversed. Short chain fatty acids (C4‐C12) were virtually absent which was surprising to find in the milk fat of a herbivore. The Red kangaroo can elaborate simultaneously the two kinds of milk fat just described in two different glands supplying a small pouch young and a large young at heel respectively. It is suggested that early milks containing far more palmitic than oleic acid may only be found in mammals that have very special young such as the echidna, platypus and marsupials.The structure of the mammary gland from the condition found in the very young virgin doe to that of a doe suckling a 312‐day young is described. The Red kangaroo has four mammary glands one of which, suckling a small pouch young, differentiates and grows along with growth of the pouch young and produces milk with a high palmitic acid content, another, suckling a young at heel, has large fully differentiated and thin‐walled alveoli, while the other two (non‐suckled) show progressive regression from the condition at birth, followed by redifferentiation at c. 128th day of lactation, both activities being independent of the activities of the lactating glands.
The annual cycle of the Rufous‐collared sparrow (Zonotrichia capensis) in three biotopes in north‐western Argentina
Authors: King James R. 
Published: August 2009

This investigation delineates the phenology of the annual cycle (gonadal activity, nesting, moult, behavioural events) in the Rufous‐collared sparrow and attempts to identify the environmental factors involved in the temporal coordination of the annual cycle with environmental seasonality. Populations of sparrows were studied in arid chaco plains, subtropical foothill transition zone, and mountain semi‐desert along a 100‐km east‐west transect at 26.9d̀S in the eastern piedmont of the Andes. This is a region of summer rainfall and winter drought characterized by a temporally unpredictable onset of vernal rains and vegetative rejuvenation.All three populations have a strong gonadal cycle including a period of histological collapse and reorganization. Measureable gonadal growth began in spring concurrently in all three populations when the daily photoperiod surpassed about 12 hours. The rates of gonadal growth in the log‐linear phase were alike in the chaco and mountain populations, but were only 35–45% of the rate in the intervening foothill population. The earliest nestings in all populations were closely correlated with the first growth of vegetative ground cover, but less closely correlated with other environmental variables. The growth of ground cover to an arbitrary index stage differed by several weeks in the three biotopes, and the onset of the nesting season differed accordingly. Rufous‐collared sparrows in this region nest almost exclusively on the ground in dense grass, and are evidently dependent on its concealment. Gonadal regression began at different times in the three populations and was not uniformly correlated with any obvious changes in the condition of the habitat. In all cases, regression began after the summer solstice, and thus coincided with decreasing daylength.Postnuptial moult in adults began almost simultaneously in all three populations regardless of the phase of the nesting cycle. Moult (suspended temporarily in some individuals) thus overlapped the end of the nesting season in the chaco and foothill populations, but not in the mountain population. Postjuvenal moult in immatures also began almost simultaneously in the three populations, about two weeks later than the onset of postnuptial moult.The temporal coordination of the annual cycle of Rufous‐collared sparrows in northwestern Argentina appears to be controlled basically by the annual photocycle, with habitat conditions (probably vegetative growth in spring) acting as essential modifiers in the final adjustment of nesting to local conditions. This system allows the sparrows to exploit suitable nesting conditions as soon as they occur each year in a temporally unpredictable environment in which an exclusively photoperiod control of the gonadal cycle would be deleterious in a large proportion of years.
Vascular physiology of the ascidian Pyura praeputialis
Authors: Goddard C. K. 
Published: August 2009

Blood pressure was measured at both ends of the heart of Pyura praeputialis (Heller) after removing the tunic.For posterior anterior heart waves average upstream pressures were 23–25 mm H2O (positive): corresponding downstream pressures averaged 8 mm H2O (negative). For anterior	posterior waves average upstream pressures were 17–18 mm H2O (+) and downstream values were 7–8 mm H2O (‐). Maximum pulse amplitudes recorded were about 30 mm H2O (upstream).Speed of the peristaltic wave was 25‐31 mm/s. In one experiment the speed was demonstrably different over the two halves of the heart (48 mm/s over the rear half and 29 mm/s over the front half).Number of peristaltic waves per series (i.e. between successive reversals) varied from 20 to 178. Duration of each series varied from 120 s to 690 s. Wave frequency ranged from 8 to 21 per min. Reversal frequency ranged from 5 to 30 reversals per hour.Most preparations showed periods of reduced heart activity (“rest periods”) during the the 2 4 h of the experiment. All showed spasmodic contractions of the mantle muscles which caused pressure “surges” in the vascular system.It is shown that, in both directions of beat, most or all of the pressure wave is contributed by the front half of the heart (half towards which peristaltic wave is travelling). This can be related to the “reversed spiral” structure of the heart: each “half” of the heart (i.e. each spiral) serves primarily as the pump for one direction.
The role of the notochard in forward and reverse swimming and burrowing in the amphioxus Branchiostoma lanceolatum
Authors: Webb J. E. 
Published: August 2009

Analyses of high speed cinefilm have shown that amphioxus swims either forward or backward with undulatory movement generated at the leading end, the wave of displacement passing along the body with increasing amplitude. The leading end, whether this is “head” or tail, is evidently more rigid than the trailing end, flexibility at each end changing with reversal in direction of swimming. It is suggested that control of the amplitude of the waves of displacement in different regions of the body in swimming is a function of the notochord, contraction of the muscular notochordal plates increasing its stiffness. Connections between the central nervous system and the notochordal plates via the notochordal pits are already known to exist.As exposure to light invariably induces swimming in dark–adapted animals, it seems probable that the eyes function in initiating movement. The rate of increase in number and size of the eye cups during larval and adult growth and their pattern of distribution in the nerve cord are given. In the adult the eye cups occur predominantly in the anterior and posterior regions of the body. This may be of significance in providing the stimulus for changes in flexibility of these regions in swimming.High speed cinefilm has also shown that amphioxus can burrow “head” or tail‐first and move through sand in a forward or a reverse direction. It is suggested that rapid reversal of direction is of greater importance in movement through sand than in swimming.
Observations on the Cladocera of Lake George, Uganda
Authors: Burgis Mary J. 
Published: August 2009

Seven species of Cladocera were recorded from the shallow, equatorial Lake George in Uganda, during the period 1967–72. Of these only three, Moina micrura Kurz, Ceriodaphnia cornuta Sars and Daphnia barbata Weltner, are found in the open water and they form a small proportion of the total zooplankton biomass, which is dominated by a cyclopoid copepod. All three species are found throughout the year and carry parthenogenetic eggs at all times. They are smaller species than those predominating in some other East African lakes and some comparisons are also made between C. cornuta and four other species of that genus studied in Great Britain. The mean body lengths and clutch sizes of ovigerous females of C. cornuta vary little through the year. This is, presumably, a reflection of the relatively constant environment in Lake George. Alona poppei is only found in the open water intermittently and is thought to be swept from the peripheral swamps during heavy rains.The general scarcity of Cladocera in Lake George is thought to be due, either to a shortage of food particles of suitably small size in the phytoplankton, which is dominated by large blue‐green algae, or to predation. Although Cladocera are certainly eaten by fish, quantitative data, with which to substantiate either of these hypotheses, is lacking.
Chance and change in British Long‐tailed field mice: (Apodemus sylvaticus)
Authors: Berry R. J. 
Published: August 2009

The Long‐tailed field mouse (Apodemus sylvaticus (L.)) has undergone a marked degree of racial differentiation on the islands of the north‐west Atlantic (Iceland, Shetland, and the Hebrides). The differences have arisen as a result of the colonization of these islands after the Pleistocene by small numbers of animals carrying alleles in different proportions to those in the parental population. In contrast, the populations on some islands to the south of Britain (Jersey and Guernsey in the Channel Isles, and St. Mary's in the Isles of Scilly) are similar to A. sylvaticus from the mainland of Britain, and are likely to represent the descendants of mice which survived the Ice Ages (A. sylvaticus populations on the smaller islands–Alderney, Sark, Herm and Tresco–differ markedly from their closest relatives, and probably represent the results of recolonization following extinction in the same way as on the glaciated islands to the north).On the mainland of Britain there is a fairly clear distinction between two groups: western and central populations, and eastern ones (which have closer affinities to French mice than western British ones). It is suggested that the two mainland British “races” may have diverged in Pleistocene refuges. Since no pelage or size genes are involved in the divergence, it would not be expected that they would be taxonomically distinct.The data on which these conclusions are based derive from the incidence of 20 nonmetrical variants in the skulls of 1096 mice from 22 series.
The aggressive behaviour of individual male polecats (Mustela putorius, M. furo and hybrids) towards familiar and unfamiliar opponents
Authors: Poole Trevor B. 
Published: August 2009

Experiments are described which were designed to investigate the significance of individual differences in aggressiveness between polecats and the relation between the familiarity of the opponent and the pattern and outcome of fighting.The behaviour of Mustela putorius, M. furo and hybrids between the two species was investigated in an indoor arena of 16 m2.Two kinds of fighting between male polecats were recorded, “companion fighting” between cage mates, in which biting was inhibited and neither of the opponents became intimidated and “uninhibited fighting” between unfamiliar individuals from which a winner and loser generally emerged and a rank order formed.Individual differences in aggressiveness were assessed by means of a scoring system which statistical analysis showed, generally, to be consistent for any one individual. The rank of an animal, however, was found not to be invariably related to its aggression score.A number of other factors influencing fighting were investigated, the earlier introduction of one individual into the arena increases its chances of winning a fight; when offered a choice, male polecats fight strangers in preference to cage mates; and the separation of a group of cage mates for as little as 48 hours induces them to behave towards one another like strangers with the result that a rank order is formed. Factors which had no apparent effect on fighting between males were the weight of the individual or the presence of females.The attributes of familiar and unfamiliar opponents are discussed in the light of these findings.
The breeding pattern of the Soft‐furred rat, Praomys morio in an evergreen forest in Southern Uganda
Authors: Okia N. O. 
Published: August 2009

Observations were made on the breeding of Praomys morio in a lake shore forest in Uganda, during a mark‐release‐recapture programme whose other aim was to study the role of rodents in the epidemiology of arboviruses. Because of the few numbers of animals captured other means of increasing reproduction data were employed. These included calculating the months of birth of very young animals from their weights.It was found that pregnancies and births were more numerous in January, April, July, August and November. Recruitment of young animals occurred in three peaks, viz; February, June and September, corresponding to low rainfall months. It was concluded that P. morio shows some form of seasonality in its breeding that may be related to rainfall.
A probable homologue of the clavicle in the holostean fish Amia calva
Authors: Liem Karel F. , Woods Loren P. 
Published: August 2009

The two pairs of appendages associated with the throat region in Amia are described.The posterior serrated appcndage of Amia calva is considered a homologue of the clavicle. This theory is based on topographical similarity (a bony element situated in front of the ventral part of the cleithrum and overlapping the anterior margin of the adjoining part of the cleithrum), structural similarity (cellular bone with ridges bearing denticles arranged in distinct patterns), ontogenetic similarity (early ontogenctic ossification with other dements of the dermal shoulder girdle prior to the appearance of scales), and phylogenetic cvidcnce (presence of similar elements in the caturid Furo).Although the anterior serrated appendage of A. calva exhibits structural and topographical similarities to both scales and clavicles, the ontogenetic evidence favours an homology with scales.The ossicles located dorsolateral and lateral to the anteroventral part of the cleithrum in Lepisosteus oculatus share structural and topographical similarities to both scales and clavicles. However, ontogenetic evidence indicates that these ossicles are scales rather than fragmented clavicles.
Some mechanisms involved in host recognition and attachment of the glochidium larva of Anodonta cygnea (Mollusca: Bivalvia)
Authors: Wood Elizabeth M. 
Published: August 2009

The ways in which the parasitic glochidium larva of Anodonta cygnea L. make initial contact with their host are investigated, and it is suggested that the thread can act as an attachment organ.Glochidia discriminate during the initial stages of attachment, and select a suitable host. Selection is achieved by the glochidia recognizing and responding to certain substances which are associated with the surface of the fish. Although these substances remain unidentified, they are almost certainly not constituents of the intact epidermal mucus. They may, however, be formed by bacterial degradation of the mucus.Prior to the formation of a cyst, a glochidium maintains its hold by grasping the host tissue between the two shell valves. The valves are held together primarily by the adductor muscle, and the hooks help to grip the host.
The physiology of chronic water deprivation in the California ground squirrel (Spermophilus beecheyi): relevance to natural populations
Authors: Baudinette R. V. 
Published: August 2009

Monthly analysis of plasma and urine was carried out in a natural population of the ground squirrel Spermophilus beecheyi. Ionic and osmotic concentration of the urine varied greatly with season, reflecting changes in water availability, diet, and perhaps adrenal gland activity. Plasma concentrations remained constant over the twelve month period.In laboratory tests, urine and plasma were analyzed in animals trapped in both summer and winter, and in two laboratory stocks; one maintained on saline solutions the other on minimal water for maintenance of weight.The comparison between field and laboratory suggested that minimal water and saline treatments of this type were more stressful than field conditions, even in this period of very low rainfall. Minimal water rations in the laboratory produced renal hypertrophy and changes in plasma osmotic concentrations, both conditions not found in summer field populations. Control ad libitum groups suggested a possible seasonal difference in urine sodium levels which should be considered in laboratory water balance testing.Although the commonly used indications of water economy in rodents may be valid for laboratory comparisons, these results indicate the difficulties in field interpretation.
Structure and keratinization of the skin of a fresh‐water teleost Notopterus notopterus (Notopteridae, Pisces)*
Authors: Mittal A. K. , Banerjee T. K. 
Published: August 2009

The microanatomy of the skin of an air‐breathing fish, Notopterus notopterus is described and related to the distribution of various histochemical constituents involved in keratinization.In addition to distinct unicellular mucous glands, secreting sulphated acid mucopolysaccharides, the epidermis of TV. notopterus is mainly composed of polygonal cells containing sulphated acid mucopolysaccharides, concentrated in the distal peripheral areas of the cells. The mucopolysaccharide contents of these polygonal cells gradually increase as they mature and move towards the outer surface. They may ultimately form a part of the protective keratinized layer.The mature keratinized cells give positive reactions with Papanicolaou's stain, contain cystine bound SS groups, cysteine bound SH groups, calcium and moderate amounts of sulphated acid mucopolysaccharides. These cells having flat pyknotic nuclei undergoing karyolysis, are fused together at their lateral margins to form an intact sheet which is frequently seen sloughing off from the underlying epidermal cells.The process of cornification in N. notopterus is comparable to that of the amphibians and the aquatic reptile–the turtle.There exists a well developed lymphatic system in between the cells of the stratum germinativum having lymphatic spaces often penetrating deep into the middle layer. This is an adaptation which contributes largely to the protective function of the fish skin.The layers between the scales and the basement membrane contain sulphated acid mucopolysaccharides. This together with keratinization has been correlated with the peculiar mode of life of the fish, often facing the problems of desiccation.The epidermis is anchored on the dermis by fine strands of collagen fibres connecting the basement membrane and the scales, and by numerous fine papilla‐like projections of the basement membrane projecting in between the cells of the stratum germinativum.Numerous fine elastic fibres in the connective tissue pockets in which scales are lodged, provide for free movement of the scales when the body of the fish is bent during swimming.Pit organs singly or in groups are found distributed in the epidermis.