bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reproduction in rats of the subgenus Rattus.
Authors: HARRISON J. L. 
Published: August 2010

SUMMARY.

Records of fertility (sperm in male, pregnancy in female) have been made on a large number of small mammals collected for examination by the Scrub Typhus Research Unit stationed at Kuala Lumpur. Those of rats of the subgenus Rattus, which includes the commensal forms, are summarized here.
The rats concerned are Rattus rattus diardii, a house rat; R. r. jarak, an island form related to it; R. r. jalorensis, a forest and plantation rat which is a pest of oil palms; R. r. argentiventer a grassland rat, which is also a pest of ricefields and is important in the dissemmination of scrub typhus; R. exulans, a rat of very wide range, which can be a house‐, a field‐, or a forest rat; and R. annandalei, a rare forest rat.
The sex ratio of each was found to approximate to equality. The significant departures from equality observed were explicable for R. r. diardii by a higher death rate among males than females, for R. r. argentiventer by a greater range and hence a higher trapping rate among males.
The weight of the testes of mature males of R. r. jalorensis, jarak, and R. exulans was found to be 5 or 6 per cent, of the body weight, that for R. r. diardii, argentiventer, and R. annandalei about 3 per cent.
Mean weights at which fertility commenced were estimated from the regression line of fertility rate on body weight.
Mean weights during the first and last pregnancy were similarly estimated from the regression line of pregnancy rate on body weight.
Mean embryo numbers, and the distributions of litters of different sizes are given. For only two rats, R. r. diardii, and R. exulans was there any observed tendency for the embryo number to increase with the body weight. All but R. r. argentiventer showed signs of an intra‐uterine mortality.
The distribution of embryos between right and left horns of the uterus was noted. In most rats they were entirely independent, but in R. r. argentiventer there was a marked tendency for all the embryos to be on one side or the other. R. r. jarak showed a tendency for embryos to be borne on the right side.
The embryo rate is used as a measure of the reproductivity and hence of the death rate. It is concluded that the rate is probably correlated with the incidence of predation and not with the form of rat.
The unusually low reproductivity of R. r. jarak is due to an unusually low embryo number. It is suggested that this is an effect of malnutrition. The unusually low reproductivity of R. r. argentiventer is due to an unusually low pregnancy rate. It is suggested that this may be explained by the low population density of this rat.
Development and placentation of the Indian fruit bat. Pteropus giganteus giganteus (Brünnich).
Authors: MOGHE M. A. 
Published: August 2010

SUMMARY.

The uterus is bicornuate and the two horns of the uterus apparently united are separate for the greater part. Pregnancy occurs only in one horn. The ovary of both sides produces ova but the corpus luteum is present in the ovary of the pregnant side. Copulation takes place early in September and parturition in late January or early February.
The embryonic mass is at first lateral but later mesometrial.
There is an implantation cavity formed within a protruding mass of nterine endometrium. The implantation is partly interstitial.
The trophoblast cells penetrate the uterine endometrium very early in development.
The amnion is formed by eavitation.
The yolk‐sae is on the antimesometrial side and the allantoic vesicle on the mesometrial side.
The bilaminar omphalopleure becomes trilaminar by growth into it of mesoderm cells at the prochordal plate stage. The yolk‐sac placenta is formed at this stage.
The primitive trophoblast forms the syneytiotrophoblast by proliferation. It erodes the uterine mucosa, forming in later stages a syneytial shell and later replaces the whole of the protruding uterine endometrium. The basal trophoblast cells form the cytotrophoblastic cords.
The wall of the allantoic vesicle provides the vascular mesenhyme tissue. The allanto‐chorionic placenta is formed on the mesometrial side and consists of syncytiotrophoblast, cytotrophoblastic cords and allantoic vascular mesenchyme and large blood spaces containing maternal blood. In early stages, maternal endometrial cells are present but these are lost later.
There is no “inversion”.
At mid term, the allantoic vesicle extends laterally and sends out villous mesenchymal projections. At the same time, the yolk‐sac wall is withdrawn and is thrown into folds which lie first laterally and later on the mesometrial side. The yolk‐sac forms a gland and persists up to parturition.
The foetal blood cells are nucleated up to at least a month prior to parturition.
The entire endometrium which protrudes into the uterine lumen is converted into a placenta. On the mesometrial side it is attached to the uterine myometrium by a narrow stalk. Large, round decidual cells are present in this region.
The placenta is at first horse‐shoe shaped. Later the loops contract; the middle portion thickens and finally it assumes the form of a dise on the mesometrial side.
There is no decidua capsularis.
The cytotrophoblastic cords become thin and elongated; they branch and anastomose. The placenta is mesometrial, discoidal, labyrinthine and haemochorial.
The reaction to light and its inheritance in grain‐weevils, Calandra granaria (L.) (Coleoptera‐Curculionidae).
Authors: RICHARDS O. W. 
Published: August 2010

SUMMARY.1. While most grain‐weevils. Calandra granaria (L.), move away from a source of light, a small fraction of the population move towards it.2. It has been shown by selection carried out for two generations that there are two genetic types of weevils, those which are negative to light and those which are almost indifferent to it.
A new parasitic mite from the nasal cavities of the South African toad Bufo regularis Reuss.
Authors: LAWRENCE R. F. 
Published: August 2010

SUMMARY.A new species of the genus Ricardoella, living in the nasal cavities of the South African toad, Bufo regularis, is described. The features in which it differs from the two known species of the genus, R. limacum (Schrank) and R. crassidens (Berlese & Trouessart), are enumerated. It does not occur in large numbers, but does not appear to be uncommon on Bufo regularis. Reasons are given for believing that the mite may be a blood feeder rather than a mucus feeder, thus differing from R. limacum.
The role of cuticle growth in the feeding process of ticks.
Authors: LEES A. D. 
Published: August 2010

SUMMARY.

Those ticks which are adapted for ingesting exceptionally large blood meals possess the ability to secrete new cuticle during the period of attachment to the host. This mechanism is described in the female of Ixodes ricinus.
The period of engorgement can be divided into two phases. (a) During the first, which lasts for seven days, the body weight rises gradually from 2 mg. to about 50 mg. In this period of active cuticle synthesis the endocuticle increases in thickness from 50μ to 105μ. The moderate increase in surface area is due to the molecular growth of the cuticle and not to its distension by the gut contents. Blood is ingested continuously but slowly during this phase. As, however, digestion and assimilation are proceeding actively, the lumen of the gut remains almost empty, (b) During the second phase, which occupies one day or less, cuticle deposition ceases and a large volume of blood is rapidly ingested. The body weight rises abruptly to over 200 mg. The cuticle is stretched and returns to an overall thickness of about 50μ.
During the deposition of cuticle the epidermis becomes greatly hypertrophied. The nuclei enlarge, one or more nucleoli appear and the cytoplasm becomes heavily charged with ribonucleie acid and alkaline phosphatase.
The processes of growth and stretching greatly modify the cuticle structure. The pore canals, numbering about one hundred and thirty per epidermal cell, become more widely separated during the growth phase. The mechanical stresses produced by stretching cause the pore canals to be pulled still further apart, and to assume an oblique or sinuous course.
All species of the family Ixodidae, and usually all instars of the same species, grow their cuticles during engorgement. (The larvae and nymphs of Haemaphysalis inermis are probable exceptions.) The Ixodidae are therefore slow feeders. Among the Argasidae. the larvae commonly possess the growth mechanism and therefore feed slowly. The nymphs and adults accommodate the smaller blood meal simply by stretching the preformed cuticle. They therefore feed rapidly. (The second nymphal instar of Otobius megnini is probably an exception.)
The large size of the blood meal in the Ixodidae has permitted a reduction in the instar number without any corresponding sacrifice in fecundity. This may be advantageous because host‐finding is also thereby reduced. However, the slow process of cuticle growth entails the lengthy carriage of the tick by the host and this may cause dispersal of unfavourable environments. The suppression of feeding and the cuticle growth phase in the larvae of Ornithodoros moubata and O. savignyi suggests that under certain conditions selection has in fact operated in the reverse direction.
The hair tracts of some American marsupials.
Authors: BOARDMAN W. 
Published: August 2010

SUMMARY.The hair tracts of Marmosa cinerea, M. murina, Chironectes minimus. Didelphis marsupialis var. azarae, Didelphis marsupialis var., Didelphis sp. and Metachirus oppossum, all members of the marsupial family Didelphidae are recorded.The several tract patterns are shown to be classifiable into a series of stages of increasing complexity in terms of divergent and convergent centres.
A new subterranean gammarid (Crustacea) from Britain.
Authors: SPOONER G. M. 
Published: August 2010

SUMMARY. Niphargus glenniei is a new species discovered in limestone caves near Buckfastleigh, S. Devon, where it was first collected and suspected of being peculiar by Brig. E. A. Glennie of the Cave Research Group. A full description is given. The species is small, and the male sex has not yet been recognized.The nearest possible relatives on the continent are N. arndti, known from four localities in Silesia, and N. nolli, known from two localities in the middle Rhineland, both small species in which the mandibular palp shows an unusual simplification. However, differences between N. glenniei and these two species are considerable, and the resemblances may conceivably be but the effect of convergence. If so, N. glenniei is quite isolated from the rest of the genus.Schellenberg's genus Niphargellus is not to be considered valid, an opinion enhanced by the discovery of N. glenniei.In view of the poverty of the British subterranean arthropod fauna, and the lack of endemic forms, this discovery is of particular interest.
Africa since the Mesozoic: with particular reference to certain biological problems.
Authors: MOREAU R. E. 
Published: August 2010

SUMMARY.

The existing information about the Tertiary geology and elimate of Africa is collated and discussed critically.
There is no evidence for a revolution in the climate and fauna of Africa (following incursion from Asia) after the Miocene.
The arguments in favour of the equator having remained in its present position through the Tertiary are regarded as stronger than those in favour of its southward shift (through some 45).
The passerine avifauna of Africa is analysed by biomes and with respect to its affinity with the avifaunas of Europe and Asia.
The difference between the lowland evergreen and the savanna avifaunas is great, at the generic as well as at the specific level; that between the lowland evergreen and the montane evergreen is nearly as great–so much that they must largely have evolved in isolation from each other.
Floristic evidence is adduced and compared with the faunistic.
The bio‐geographical data are discussed in relation to the geological and the climatic.
Seasonal variation in the thyroid gland of the Minnow, Phoxinus phoxinus L., with some observations on the effect of temperature
Authors: Barrington E. J. W. , Matty A. J. 
Published: August 2010

Summary.A quantitative assessment has been made of the height of the cells of the follicular epithelium of the thyroid gland of the Minnow, Phoxinus phoxinus L., as an index of the activity of the gland at different seasons of the year. It is possible, despite the considerable degree of variation which occurs, to demonstrate siginificant fluctuations which indicate that the activity is at its maximum during the early months, from about February to May, during which period the maturation of the germ cells is known to be completed. The maintenance of minnows at constant temperatures for fifty‐seven days gives no evidence of an inverse relationship between temperature and cell‐height such as is known to exist in certain homoiotherms, but actually suggests a direct one. It seems unlikely, from the available data, that, the thyroid fluctuations can be a response to temperature changes in the environment, and it is concluded that there is an indication in the minnow, as elsewhere in the vertebrates, of some correlation of the activity of the thyroid gland with the phases of the reproductive cycle, the causal basis of which is, however, obscure.
Ecological changes in the Palaearctic Region since the Pliocene.
Authors: Moreau R. E. 
Published: August 2010

SUMMARY.The climatic sequence during and since the Pleistocene is summarized. For Europe, four glaciations are accepted, separated by interglacials during which the climate was more genial than the present. Moreover, each glacial and interglacial was divided into phases. Eastwards these vicissitudes diminished: only two glaciations. are discernible over most of Siberia and eastern Siberia has witnessed altogether less climatic change since the Pliocene than any other part of the Palaearctic.The changes in the level of the oceans owing to the alternate locking‐up and melting of masses of water in the ice‐caps produced fluctuations of much local importance in the coast‐lines during the Pleistocene.The vegetation of Europe during the best documented glacial phase, namely Phase 2 of the Last Glaciation, is discussed on the basis of recent maps. The most important feature is that trees were practically eliminated from Europe north of a line through the Pyrenees, the southern foot of the Alps and the Carpathians, except for a strip of wooded tundra and wooded steppe across central Russia. Deciduous species were confined to the southern end of the Iberian, Italian and Balkan peninsulas, and the coasts of Barbary and Asia Minor. These (Phase 2) conditions are dated about 70,000 years ago; they recurred to a considerable extent in Phase 3, about 25,000 years ago. Moreover, after the first post‐glacial (Allerød) advance of the trees to as far north as the Baltic, the “Younger Dryas” cold snap, only some 10,000 years ago, again eliminated most of the trees from north of the Alps.By contrast with the foregoing, at the height of the interglacials deciduous and coniferous forest respectively extended several degrees further north than at present; at least in Europe, if not in Asia, treeless tundra was probably eliminated from the arctic lowlands.At the maximum glaciation (the Third), the tree‐growth was probably not much more strictly limited in western and central Europe than it was in Phase 2 of the Last Glaciation but in European Russia tundra and cold treeless steppe extended south right to the Black Sea and the Caspian.In Palaearctic Asia the vegetational conditions during the glaciations are more obscure than in Europe; but during the Last Glaciation trees appear to have existed at least sparsely all across Siberia.Finally, Dr. Brooks, Dr. Dimbleby, Dr. D. Lack and Professor Zeuner have all been good enough to criticize this review in draft. Its final errors and omissions are of course my own responsibility.
Some characters of the skulls and skins of the European Polecat, the Asiatic Polecat and the domestic Ferret.
Authors: Ashton E. H. , Thomson A. P. D. , Zuckerman S. 
Published: August 2010

SUMMARY

Certain characters of the skins and skulls of (a) the European polecat Putorius putorius putorius, (b) the Asiatic polecat Putorius putorius eversmanni and (c) the domestic ferret Putorius putorius furo have been compared.
The ferret resembles the European polecat more closely than the Asiatic in:(a) the extent of the black area of the tail;(b) the overall size and shape of the skull;(c) the position of the postorbital constriction;(d) the proportions of the pre‐ and post‐zygomatic parts of the skull:(e) the shape of the nasal bones;(f) the hooking of the hamular process.
It resembles the Asiatic polecat more closely than the European in:(a) the proportion of individuals in which the frontal band is continuous;(b) the degree of constriction of the postorbital region.
The skull of the ferret is more variable than that of either the European or Asiatic polecat.
The data are inadequate to decide whether or not the differences between the ferret and European polecat are too great, to permit the view that the ferret of today is merely the descendant, of a domesticated variety of European polecat.
It is suggested that the changed breeding system and selective forces which operate on the captive animal, may be conducive to the origin of differences of this type.
The evolution of the pelagic alciopid and phyllodocid polychaetes.
Authors: Dales R. Phillips 
Published: August 2010

SUMMARYThe morphological adaptations of the alciopid and lopadorhynchine polychaetes for a pelagic mode of life are compared, with particular reference to the organs concerned with feeding and reproduction. Both groups are predatory, but feed in different ways; Lopadorhynchus has poorly‐developed eyes but long cirri, anterior segments modified for grasping, and large pharyn‐geal glands; alciopids have large eyes and the most advanced have long eversible proboscides. Many alciopids have evolved a copulatory mechanism whereby the sperm are transfered to the female which stores them in receptacula until required. The phylogenetic relationships of the different genera are briefly described.
The buccal and pharyngeal mucous membrane in urodeles
Authors: Elkan E. 
Published: August 2010

SummaryHistological investigation of the buccal and pharyngeal mucous membranes of Triturus vulgaris, Salamandrina perspicillata, Aneides ferreus, Aneides flavipunctatus, Aneides lugubris, Desmognathus, fuscus, Eurycea bislineata and Hydromantes genei suggests that gular vibrations are not concerned with gas exchange but with the sense of smell. They should not be interpreted as respiratory.
THE RELATIONSHIP BETWEEN THE LENGTH OF THE JAW AND THE LENGTH OF THE MOLAR SERIES IN SOME EUTHERIAN MAMMALS
Authors: WILLIAMS G. 
Published: August 2010

SUMMARYThe relationship between the length of the molar row and the length of the lower jaw in mammals is expressed by the allometry equation y=bxk.A single formula cannot be applied to all the Eutheria because the value of k, the constant differential growth ratio, varies from group to group.Variation in k would appear to be adaptive, for it increases from a value of less than unity in carnivores, through insectivores and omnivores, and exceeds unity in herbivores.The value of the constant b decreases as k increases, with the result that most mammalian skulls have the same length of molar row when the jaw length lies between 90 and 110 mm.When the full complement of molars is not present, there is a reduction in the extent of the molar row. In groups with a common ancestry, this reduction is proportional to the number of teeth which are lost, but a history of tooth enlargement may partly compensate for the decrease.The zalambdodont Insectivora are anomalous in that the molar row occupies proportionally less of the jaw than in most mammalian orders. The genera may be arranged in a graded sequence, the first members of which overlap the remaining Eutheria while the final members depart widely.In Tenrec and Hemicentetes the length of the molar row is independent of jaw size.In view of the variation in the value of the constants b and k for both the zalambdodonts and the other Eutheria the paurodont/zalambdodont line cannot be set in contrast to a marsupial/eutherian line.These conclusions apply with equal force whether the molar row is related to the total jaw length or only to that part of the jaw lying posterior to the last pre‐molar.
THE FOSSIL CARNIVORES OF THE TRANSVAAL CAVES: FELINAE
Authors: EWAR R. F. 
Published: August 2010

SUMMARYThree fossil Felinae are described. These are a leopard differing only slightly from the living species, and named Panthera pardus incurva; and two species of lion‐like animal, which are not identical with the living species. The specimens of the latter two species are very fragmentary, and they have not been named, but are merely referred to as the Swartkrans and the Kromdraai “lions”. It is suggested that the latter may possibly be identical with Panthera shawi (Broom).It is concluded that the differences in the feline faunas of the deposits at Sterkfontein, Swartkrans and Kromdraai indicate some difference in the ages of the deposits.
A NOTE ON THE BIOLOGY OF MARTESIA STRIATA L. (LAMELLIBRANCHIA)
Authors: PURCHON R. D. 
Published: August 2010

SUMMARY

Healthy specimens of Martesia striata L. were obtained from timbers in the Johore Straits in March 1953, and were examined immediately.
The siphonal process is of type “C” and resembles that of Pholadidea loscombiana.
The shell valves possess a posterior flexible uncalcified portion, comparable with the siphonoplax of Pholadidea loscombiana,
The scar of the anterior adductor muscle is smaller than that of the posterior adductor. In this respect Martesia resembles Pholadidea more closely than other genera in the Pholadidae.
In large specimens which had ceased to bore, the pedal muscles and the anterior and posterior retractor muscles of the visceral mass had atrophied. The foot also had disappeared.
The flat and homorhabdic ctenidia are of Atkins's type C 2.
The ciliary sorting mechanisms on the ctenidia and labial palps are suited for the selection of few fine particles and for the rejection of larger quantities even of fine particles. This is considered to be well adapted to life in inshore waters that may occasionally have a very high silt content.
The palps are extremely efficient sorting organs and the ciliary mechanisms on the folded surfaces are comparable with those reported for other genera in the Pholadidae.
The ciliary cleansing mechanisms on the surfaces of the visceral mass and mantle are described.
There is no appendix to the stomach. In other respects the alimentary canal is closely similar in structure and function to that of other members of the Pholadidae.
There is an anterior median fenestra joining the cavities of the distal limbs of the left and right excretory organs as is found also in Barnea parva and Zirphaea crispata.
There is a transverse connective between the left and right cerebrovisceral connectives, immediately anterior to the visceral ganglia. This transverse connective is slightly swollen to form an accessory visceral ganglion, as in other genera of the Pholadidae.
There is an indication of slight sexual dimorphism, affecting the form both of the genital aperture and of the anal papilla.