bluuebunny/crossref_metadata_2025 huggingface dataset:
On the status and relationships of the Solomon Island elapid snakes
Authors: McDowell S. B.
Published: August 2009

The snakes now calledDenisonia parandD. woodfordiare considered conspecific, but generically distinct fromDenisonia(for the AustralianD. maculataandD. devisi); they are here termedSalomonelaps parand an account is presented of the considerable island‐to‐island variation in that species. the snake now caledMicropechis elapoidesis transferred to a new genusLoveridgelaps,here believed to be closely related toSalomnelaps par, Ogmodon vitianus,andVermicella annualata;an account (quite tentative and unsatisfactory because of the paucity of specimens) of the variation inLoveridgelaps elopoidesis presented.Salomonelaps, Loveridgelaps, Ogmodon,andVermicellamake up a well defined (by the presence of an imperforate lateral process of the palatine) group of Australiasian elapids, theVermicellagroup, and a key to the genera and generic descriptions for this group are presented. The New Guinea genusMicropechis(containing onlyM. ikaheka) is a member of a different group, here called thePseudechis, containing alsopseudechis, Austrelaps(forA. superbus), andSuta(for the generaSuta, Parasuta,andUnechisof Worrell, and the speciesFasciataandPunctata, referred toDenisoniaby Worrell, andFlagellum, referred toCryptophisby Worrell). Some additional notes are given on the type ofDenisonia boschmaiBrongersma & Knaap‐Van Meeurwen (here considered a geographic variation ofSuta carpentariae),and a key to the genera ofPseudechisgroup is presented.
Growth and reproduction of Hymeniacidon perleve (Montagu) (Porifera) in Langstone Harbour Hampshire*
Authors: Stone A. R.
Published: August 2009

The shore distribution, growth and reproduction of the siliceous monoaxonid sponge Hymeniacidon perleve has been studied over a two year period in a population of the sponge in Langstone Harbour, Hampshire. The zonla distribution of the sponge is described, together with details of the seasonal variation in growth and changes in population size, and experimental determinations of the minimum growth temperature. The results of investigations of larval settlement are given and the relative importance of sexual and asexual reproduction in maintaining the population are considered.
Reproduction in the common porpoise (Phocoena phocoena) of the North Atlantic
Authors: Fisher H. Dean , Harrison Richard J.
Published: August 2009

Examination of the reproductive organs from 137 Common porpoises (Phocoena phocoena) from the Gulf of St Lawrence, the Bay of Fundy and British waters has enabled observations to be made on reproductive events. Birth in Canadian waters occurs mainly in June and July: mating takes place from june to August . The evidence indicates that females do not become pregnant every year. Birth length is 80 to 90cm; juveniles attain a length of 100 to 110 cm after three to four months. Sexual maturity is reached at a length of about 133 cm in males and 145 cm in females, probably in their third or fourth year. The corpus luteum persists throughout gestation and retrogresses from their histological characteristics. One kind possesses much acellular material and is probably a corpus albicans gravitadionis; the other consists of a mass of obliterated vessels and is the remains either of a corpus luteum of an infertile ovulation or of a lutealized follicle. Evidence indicates that there is seasonal testicular activity, reaching a maximum during July and subsiding in late August.
The life cycles and ecology of Australian lampreys of the genus Mordacia
Authors: Potter I. C.
Published: August 2009

The life cycles and ecology of two closely related species of lampreys of the genus Mordacia were studied in various rivers in south‐eastern Australia. In the Moruya River in southern New South Wales, the anadromous parasitic species, M. mordax (Richardson), has a larval life of three and a half years with metamorphosis occurring in late February or early March. The nonparasitic species, M. praecox Potter, metamorphoses at a different time (late October or November) and at a significantly longer length than M. mordax. The latter probably reflects a longer larval life in M. praecox, an estimate of which could not be obtained from the available data. Thus an extension of the larval phase, as well as a reduction in the post‐metamorphic stages, may have occurred in the evolution of nonparasitic lampreys from parasitic forms. Evidence is presented to show that seasonal differences in temperature influence the pattern of ammocoete growth throughout the year, while local differences in the density of food are responsible for differences in growth rates in different areas. The effect of flooding and reduction in the water levels on the distribution of ammocoetes is discussed. A description is given of the behaviour of metamorphosing and transformed M. mordax prior to their migration out to sea. The above data is collated with that obtained from other studies to produce an overall picture of the life cycles of the two species of Mordacia.
The ultrastructure of the cuticle of adult female Mermis nigrescens (Nematoda)
Authors: Lee D. L.
Published: August 2009

The ultrastructure of the cuticle of the adult female nematode Mermis nigrescens has been described. There is an epicuticle and three‐layered membrane covering the cuticle. The cortex is penetrated by canals which extend from the surface of the cuticle to the matrix of the layer beneath the cortex. Beneath the cortex are two layers of giant fibres which spiral around the nematode, a thick layer containing a network of fibres and a basal layer containing a vacuolated matrix material. it is thought that the epicuticle is secreted from the canals in the cortex. The possible functions of the layers in the cuticle have been discussed and similarities with the cuticle of the Acanthocephala have been noted.
Character analysis: an empirical approach applied to advanced snakes
Authors: Marx Hymen , Rabb George B.
Published: August 2009

Fifty characters of extant advanced snakes were selected for phyletic analysis, with the primary aim of determining evolutionary paths of the venomous taxa. The characters chosen showed roughly equivalent variation. States of characters were distinguished with reference to range of variation at species and generic levels. The heterogeneous, widespread and abundant family Colubridae was designated as representing the ancestral group. Direction of change in states was then determined by reference to colubrid conditions. Criteria used for judgement of direction were (1) uniqueness, (2) relative abundance, (3) correlation of derived states, (4) morphological specialization, (5) ecological specialization, (6) geographic restriction, (7) closely related taxa, and (8) correlation of applicable criteria. Two other criteria, (9) genetic structure and (10) fossil record, were not applicable.

Characters used as examples of the approach are number of palatine teeth and the pattern of the head shields. In the latter, the derivative states are correlated with particular modes of life (aquatic, fossorial and terrestrial). The familial level taxa show rather different frequency distributions in respect to the four states of this character, with one derived state unique to the viperids.

The second character, number of palatine teeth, was divided into classes by using a span covering most intraspecific variation. The resulting classes were lumped into four states emphasizing the classes of low numbers of teeth. The extreme derived states are correlated in the colubrids with distinctive modes of life (burrowing and digging) and with functional morphological specializations. The distribution of the states shows a trend toward low numbers of teeth in all the venomous families.
Larval growth in the river lamprey, Lampetra fluviatilis
Authors: Hardisty M. W. , Huggins R. J.
Published: August 2009

A series of 987 ammocoetes from the rivers Towy, Teme, and Taw have been identified as mainly L. fluviatilis (L.) on the basis of oocyte counts on female ammocoetes. The length frequency distributions for this material differs from either L. planeri or P. marinus in showing only three modes in addition to the young of the year and the length distribution of the final mode coincides with the length range for 119 metamorphosing and macrophthalmia stages of L. fluviatilis that have been found at the same sites. These animals measured from 80–117 mm in length and weights varied from 0.76–2.28 g. Metamorphosis is believed to take place in late summer and early autumn when in the majority of cases, the ammocoetes are four and a half years old. The evidence that the non‐parasitic L. planeri has a longer larval life than the closely related parasitic L. fluviatilis is thought to have some significance in relation to the evolution of the brook lamprey species.
Some aspects of osmoregulation in the Barred surfperch (Amphistichus argenteus)
Authors: Holmes W. N. , Lockwood L. N.
Published: August 2009

The osmoregulatory abilities of Amphistichus argenfeus were examined following transfer from hypertonic to hypotonic sea‐water. Although some regulatory capacity was evidenced by an increase in glomerular filtration during acclimation to hypotonic sea‐water, the fish did not appear able to counter the tendency to lose electrolytes in this medium. When compared to a truly euryhaline species, such as Salmo gairdneri, A. argenteus possessed only a limited capacity to survive in a hypotonic environment.
Life history of the Mountain hare (Lepus timidus scoticus) in north‐east Scotland
Authors: Flux John E. C.
Published: August 2009

A general description of the life history of Mountain hares is given, base on a three year field study of about 200 wild hares on a moor near Morven, Aberdeenshire, and laboratory examination of over 360 dead specimens from surrounding areas. Growth and body size, behaviour, range and movements, food and reingestion are described. More detailed information on reproduction, mortality and population counts are presented to give an outline of the population dynamics in this species.
The setae of Austropotamobius pallipes (Crustacea: Astacidae)
Authors: Thomas W. J.
Published: August 2009

The author presents here the results of an introductory study into the setal armature of the British species of crayfish, Austropotamobius pallipes (Lereboullet, 1858). Using an ordinary optical microscope, it is demonstrated that a considerable variety of setae exist on the body and appendages of A. pallipes. These setae are described, and their distribution indicated. The setae fall into two main groups:

(1) Setae with relatively thick walls and inconspicuous ampulla, and having no basal septum.

(2) Those setae with relatively thin walls, a well‐developed ampulla and basal septum. Further subdivisions of these two groups are made on the bases of outgrowths and outlines of the setal wall. Finally, the significance of the distribution and the variation, is discussed in relation to crayfish behaviour and function, linking the observed morphological facts with the results of some current electro‐physiological experiments performed on related decapods.
Breeding experiments to distinguish two sibling species of Halicarcinus (Crustacea, Brachyura)
Authors: Lucas J. S.
Published: August 2009

Hybridization experiments and various salinities were used in investigating the status of two Halicarcinus lacustris‐like, forms, one of which has no free larval stages (direct‐development) and the other of which has normal larval stages (indirect‐development).

Hybrids were produced, at least from indirect‐development female x direct‐development male crosses, but introgression of genetic material was limited to F2 hybrids from the female parental form. There were no intergrades between the two modes of development in F1 and F2 hybrids or as a response to salinity.

These forms are established as sibling species. The name lacustris applies to the direct‐development form and the other is a new species, H. paralacustris, which is described. Hybridization in the field is unlikely due to geographical and reproductive isolating mechanisms. Contrary to a previous view, it seems that H. lacustris had a recent origin in Australia and transport by water birds is suggested as the mode of dispersal through south‐east Australasia.
The external morphology of the pseudoscorpion Dactylochelifer latreilki
Authors: Gabbutt Peter D.
Published: August 2009

The external morphology of all stages of Dactylochelifer latreillei (Leach) is described. The morphogenesis of characters of taxonomic importance has been followed through all the nymphal stages to the adult. Comparison is made with the information given by Beier (1963) for the three subspecies of D. latreillei and also with Boissin's (1964) detailed description of Hysterochelifer meridianus (L. Koch) which belongs to the same family Cheliferidae.

A linear relationship exists between the successive positions of trichobothria on the pedipalpal chela according well with the growth model proposed by Gabbutt (1969). The importance of the relative positions of trichobothria is discussed in relation to the systematics of the order.

Notes are included on collection techniques and their possible bias, on the length of the breeding period as judged from the presence of females with broods and the relative abundance of the nymphs, and on the number and developmental condition of eggs carried by the females.
On differential responses of the melanophores of the Paradise fish, Macropodus opercularis
Authors: Ahmad R. U.
Published: August 2009

Chromatic adaptation of the Paradise fish, Macropodus opercularis L., to illuminated backgrounds ranging from “white” to “black” shows that the pigment is most readily dispersed in the deepest‐lying melanophores and least readily in the uppermost layers.
Oxygen consumption and body temperature of the Chuditch (Dasyurus geoffroii)
Authors: Arnold Jennifer , Shield John
Published: August 2009

The average relation between O2 consumption rate and ambient temperature in the range 9–39°C for five adult litter‐mates was found to be y= 36.237–3.6821 x+ 0.26685 x2—0.0094468 x3+ 0.00011974 x4 where y is the O2 consumption rate in ml./kg min and x is the ambient temperature in °C. The O2 consumption rates of females showed a much greater variation about this regression than did the rates of males.

This regression estimates the minimum O2 consumption to occur at an ambient temperature of 31.5°C but scatter diagrams show the thermal neutral range to extend from about 28 to 33°C.

Twenty‐six oxygen consumption rates measured at 30°C (in the thermal neutral range) had a mean value of 67% of those predicted for eutherians of similar body weights but the range extended from 40 to 105%. Prolonged (13 to 28 hours) O2 consumption measurements at the same temperature show that, in the absence of activity, comparatively low O2 consumption rates are maintained for long periods.

The linear regression equation relating simultaneous O2 consumption rates and colonic temperatures measured at an ambient temperature of 30°C estimates that O2 consumption will increase from 40 to 105% of that predicted when body temperature is raised from 34.5 to 38.7°C; and furthermore that an O2 consumption rate of 67% of the predicted should occur at a body temperature of 36.2°C.

Animals kept in small cages at an ambient temperature of 30°C were found to have mean colonic temperatures of about 34.9°C during the day when they were resting and 37.4°C in the early evening when they were active. When kept at ambient temperatures lower than the thermal neutral a similar daily cycle in colonic temperature was found but the females showed a much larger variation about the daily trend than did males.

The low O2 consumption rates maintained during inactivity and a lack of strict thermoregulation result in a relatively low body temperature and a considerable saving in metabolic energy is thereby effected. The higher colonic temperatures reached in the evening result mainly from the higher energy usage during acitvity.
Studies on the effects of abnormally high water levels on the ecology of fish in certain shallow regions of Lake Victoria
Authors: Welcomme R. L.
Published: August 2009

Between 1961 and 1964 the water levels of Lake Victoria increased abruptly. This increase produced changes around the shoreline of the lake, creating new habitats in the form of lagoons. Such lagoons were cut off from the main lake by differing widths of floating vegetation. Chemically and physically these new regions resembled small tropical fish ponds, with a nocturnal reduction in both dissolved oxygen and temperature.

The lagoons were occupied shortly after their appearance by characteristic groups of fishes, which depended for their species composition on the degree of isolation of the different bodies of water from the main lake. It was generally found that the more isolated the lagoon, the more impoverished it was in numbers of species. The most successful colonizers of these waters were Tilapia leucosticta and Haplochromis nubilus, which were present in all lagoons.

Populations of these two species showed a tendency to stunt, which was more marked in the more isolated populations. This, together with the population changes associated with isolation, suggests that the mat of floating vegetation, by reason of the de‐oxygenated conditions that exist under it, acts as a form of biological filter. Thus fish from the lake can only penetrate to the nearer lagoons, the populations in the more isolated waters remaining more or less segregated.
A method of identifying individual lions Panthera leo with an analysis of the reliability of identification
Authors: Pennycuick C. J. , Rudnai J.
Published: August 2009

A method is described of identifying lions from the patterns of vibrissa spots. “Reliability” of identification is discussed in terms of the probability of there being more than one individual with a given spot pattern in the study population, and it is shown how reliability can be improved, when necessary, by adding together information from more than one source. Means of adapting the reliability calculation to identification in other species are indicated.
Quantitative effects of three species of parasites on a population of Three‐spined sticklebacks, Gasterosteus aculeatus
Authors: Pennycuick Linda
Published: August 2009

The effects of Schistocephalus solidus, Diplostomum gasterostei and Echinorhynchus clavula on a population of Three‐spined sticklebacks from a pond in Somerset were studied. Schistocephalus was present at the highest level of infection and had the greatest effects on the sticklebacks. It caused the fish to weigh less than uninfected ones of the same length, as shown by the lower condition factor, and to grow more slowly; and it delayed the sexual maturation of fish of both sexes and prevented many from breeding. Diplostomum also had a significant effect on the condition of the sticklebacks and all three parasite species probably caused death or predation of heavily infected fish. The quantitative effects of the parasites on the condition, length and weight of the fish were calculated; seasonal changes in the condition factor could then be seen, and the growth rates for both length and weight calculated.
Control of glowing ofLampyris noctilucain the field (Coleoptera: Lampyridae)
Authors: Dreisig Hans
Published: August 2009

The start of glowing inLampyris noctilucafemales is related to a particular low level of illumination. The intensity to which individuals respond vary widely but on the average 50% of the population has started to glow at 10.14 log lux + 10 (1.4 lux). The average period of glowing is dependent on the number of males present because the females stop glowing when they have mated. The activity of the males occurs during the first part of the active period of the females, so if many males are present the period of the females is short and if few are present the period is long. The activity of the males, and therefore indirectly that of the females, is dependent on physical factors in the environment especially temperature and wind.
Some aspects of adaptation in a polymorphism for breeding colours in the Threespine stickleback (Gasterosteus aculeatus))
Authors: Semler David Edward
Published: August 2009

Polymorphism in the nuptial colouration of male Threespine sticklebacks (Garterosteus aculeatus L.) was studied. In Lake Wapato in Eastern Washington, approximately 14% of the breeding males develop typical red nuptial colouration while others develop various colours which were grouped into a non‐red category. The hypothesis was tested that red males are adaptive in Lake Wapato as a result of sexual selection and differential egg predation.

In a series of mate preference tests, females demonstrated a significant preference for red males over non‐red males. In a second experiment, using artiticially coloured non‐red males, it was shown that the females are responding to the red colouration alone. This evidence suggests that one of the selective pressures maintaining the red morph is sexual selection.

In a stomach analysis of male and female sticklebacks collected from a breeding colony it was found that 51 % of the fish examined had stickleback eggs in their stomachs. Both male and female sticklebacks eat a large number of eggs; however, males eat significantly more eggs than females. Eggs were found to be most susceptible to predation during their first four days of development. Given that red ventral colouration has threat value, red males may also be adaptive because of a reduction in egg predation within their territories in contrast to non‐red males.

One of the selective forces against red males is probably differential predation by trout (Salmo gairdneri). This trout predation has been shown to be extensive in Lake Wapato. The opposing selective forces discussed in this paper cannot maintain the polymorphism; they are only components of fitness of the colour morphs.
Limb posture and locomotion in the Virginia opossum (Didelphis marsupialis) and in other non‐cursorial mammals
Authors: Jenkins Farish A.
Published: August 2009

Past studies of mammalian posture and locomotion have been made principally on cursorial species and current concepts are stereotyped accordingly. Mammalian limbs are usually characterized in terms of vertical orientation and parasagittal excursion; the assumption prevails that this type of stance and limb movement is typical of the class.

In the present study, walking movements in eight mammalian species (Tachyglossus aculeatus, Didelphis marsupialis, Tupaia glis. Mesocricetus auratus, Rattus norvegicus, Mustela putorius, Heterohyrax brucei, and Felis domestica) were studied cineradiographically with particular attention given to limb posture and excursion relative to the parasagittal and horizontal planes. Only the cat and, to a lesser degree, the hyrax conform to the postural and locomotory pattern that has been regarded as characteristic of most terrestrial, quadrupedal mammals. In the other six species, the humeri and femora usually function in positions more horizontal than vertical and at angles oblique to the parasagittal plane. Furthermore, the excursion pattern of these species have interspecific differences; some patterns are more variable than others. The classical conception of “mammalian posture” and “mammalian locomotion” is inaccurate both as a description of the features possessed in common by living terrestrial mammals and as a hypothetical approximation of the condition in ancestral mammals. At present, non‐cursorial mammals such as the opossum and tree shrew are more realistic models on which to base deductions concerning posture and locomotion in eatly mammals.
Scale formation as related to length of young‐of‐the‐year Ide Idus idus and roach Rutilus rutilus
Authors: Cala Plutarco
Published: August 2009

The scale formation in relation to length of young‐of‐the‐year ide Idus idus (L.) and roach Rutilus rutilus (L.) is described for fish from River Kävlingeän, South Sweden. The appearance of the first scale is noted as well as the scale pattern formation.
Pituitary control of ovarian activity in the lizard, Agama agama
Authors: Eyeson K. N.
Published: August 2009

The principal ovarian structures in Agama agama are non‐yolky and yolky follicles, corpora lutea and atretic follicles. Hypophysectomy affects all stages of vitellogenesis and follicular atresia results. Atresia involves resorption and digestion of yolk by the granulosa cells, which eventually undergo a fatty degeneration. Immature follicles and corpora lutea are not affected by hypophysectomy.

Injections of 0.2 mg FSH (NIH‐FSH‐S3 ovine) on alternate days for 14 days not only maintain vitellogenesis in hypophysectomized animals, but also tend to overstimulate the small follicles to synthesize yolk. A similar dose of LH(NIH‐LH‐SII ovine) fails to maintain vitellogenesis in hypophysectomized animals, while a higher dose of 0.4 mg LH tends to overstimulate the small follicles. An unusual rupture of yolky follicles in FSH injected lizards is reported and a possible development of such follicles into corpora lutea is discussed.
Associations of Cladocera in the zooplankton of the lake sources of the White Nile
Authors: Green J.
Published: August 2009

Thirty‐one species of Cladocera are recorded from the lake sources of the White Nile. An account is given of the seasonal occurrence of the main planktonic species at eight stations in Lake Albert. The horizontal distribution of species in Lake Albert was studied by means of vertical hauls taken at intervals along the length of the lake, and along transects from the shore to the middle of the lake. It is possible to distinguish an inshore group, consisting of Moina micrura and the helmeted form of Daphnia lumholtzi, and an offshore group with Ceriodaphnia reticulata and the monacha form of Daphnia lumholtzi. The validity of these groups is demonstrated by analyses of percentage co‐occurrence, correlation and regression. Diaphanosoma excisum and Ceriodaphnia cornuta overlap these two groups. These distributions can be explained by the combined operation of two major factors: the presence inshore of the zooplanktivorous fish Alestes baremose, and competition between cladoceran species of similar sizes. The overlapping of the inshore and the offshore groups by Diaphanosoma excisum and Ceriodaphnia cornuta can be explained by their sizes differing from the other main species sufficiently to reduce competition.

Similar transects on Lake Edward again reveal Moina micrura as an inshore form and the monacha form of Daphnia lumholtzi as an offshore form. Ceriodaphnia reticulata is replaced in Lake Edward by the similarly sized C. dubia. The helmeted form of Daphnia lumholtzi was not found in the samples from Lake Edward, but it is apparently replaced by Daphnia longispina, although this species also increases in abundance offshore. In Lake Victoria both the helmeted form of D. lumholtzi and D. longispina are found, but their distributions have not been studied. Lake George has D. barbata as the only species of the genus, and the samples from Lake Kyoga lacked the genus completely.

In most of the planktonic Cladocera from the lake sources of the White Nile the size of the eye is related to the size of the carapace, but the horned form of Ceriodaphnia cornuta from Lake Victoria has a relatively smaller eye than the unhorned form from Lake Albert. This may be caused by selection pressure exerted by the small planktivorous fish Engraulicypris argenteus.

Within one lake the numbers of Cladocera under one square metre increase with the depth of the station. This implies utilization by the Cladocera of an environmental resource related to total depth. This resource may simply be space. When the numbers per unit volume are calculated there is no apparent relationship to the depth of the station. With the exception of Lake Kyoga the lakes can be arranged in a series of increasing conductivity and increasing numbers of Cladocera per unit volume.
A multivariate study of the external measurements of the Humpback whale (Megaptera novaeangliae)
Authors: Machin David , Kitchenham Barbara L.
Published: August 2009

The method of principal components is applied to data of the external measurements of the Humpback whale (Megaptera novaeangliae). The first two components are found to summarize the main features of the data and are used to compare differences between the sexes and of the time and locality of capture. Suggestions are made as to how a reduction in the number of characters measured may be achieved in subsequent studies.
Ecological studies on crater lakes in West Cameroon Zooplankton of Barombi Mbo, Mboandong, Lake Kotto and Lake Soden
Authors: Green J.
Published: August 2009

The zooplankton of four crater lakes in North‐west Cameroon has been studied by means of vertical hauls from the bottom to the surface. Two of the lakes are deep, with sparse phytoplankton, while the other two are shallow with dense blooms of blue‐green algae. All the lakes are without planktonic Cladocera. In Lake Kotto, Mboandong and Barombi Mbo the dominant zooplankter is Mesocyclops (Thermocyclops) hyalinus, which is replaced in Lake Soden by Mesocyclops leuckarti. Larvae of Chaoborus are present in all the lakes. In the two deep lakes, Soden and Barombi Mbo, the dominant rotifer is Polyarthra dolichoptera, but in the two shallow lakes, Kotto and Mboandong, three species, Hexarthra mira, Brachionus fakatus and B. caudatus, make up the bulk of the rotifers.

In Barombi Mbo during the daytime most of the zooplankton was in the top 20 m, but most of the Chaoborus larvae were below 20m.

The standing crops of zooplankton in these lakes are low compared with those of lakes in the Kigezi District of Uganda.

The most remarkable feature of the zooplankton in these lakes is the occurrence of dwarfed forms. Both species of cyclopoid copepods and the eight identifiable species of Rotifera are smaller here than in most other localities. Factors which may be associated with this dwarfing are low latitude with constant high temperature, low phytoplankton availability, and the low ratio of drainage area to lake area.
The neurosecretory system of the eyestalk of Carcinus maenas (Crustacea: Decapoda)
Authors: Smith G. , Naylor E.
Published: August 2009

The optic ganglia neurosecretory cells of male and female Carcinus maenas during intermoult are distinguishable into six types based on size, location, appearance and method of secretory material release from the perikaryon. Release occurs via the sinus gland and also, in one case, directly into blood capillaries among the neurosecretory cells themselves. The sinus gland consists of axonal extensions of the neurosecretory cells; no secretory granules are produced there and nuclei observed between the axonal endings are those of ill‐defined glial cells.
Bimodal distribution of constant frequencies in some hipposiderid bats (Mammalia: Hipposideridae)
Authors: Pye J. D.
Published: August 2009

Constant frequency echolocation signals of the Rhinolophidae and Hipposideridae have generally been found to occupy narrow bands, at least within single populations. Examination of three species of Hipposideridae from a cave in Kenya shows a wide spread of frequencies in each case. In Hipposideros commersoni the pulses occur in two bands at 56 and 66 kHz with a silent interval of 8 kHz. Single individuals in isolation use only one of these frequencies and this is correlated with their forearm length. It may be that two forms of subspecific rank were cohabiting, but it may be significant that the width of the silent band is just wide enough to prevent interference from band‐spreading due to reflection from beating wings when several bats are flying together. In Triaenops afer and Hipposideros caffer there is a suggestion that the bats leave silent bands when in groups but use more varied individual frequencies when isolated. This impression might be due to sampling error and the position is little clarified by examining other populations. A group of Asellia tridens from Egypt occupied a single, fairly narrow band of frequencies. Further examination of these and other constant frequency species with a simple detector would be of interest in resolving the position.
Variable resonance in constant frequency bats
Authors: Roberts Laurence H.
Published: August 2009

Bats of the two closely related families Rhinolophidae and Hipposideridae, and also Chilonycteris rubiginosa of the family Phyllostomatidae, emit echo‐location pulses with a relatively long portion of constant frequency followed by a rapid frequency sweep. The greatest amplitude occurs either during the constant frequency or at some point in the sweep with the constant frequency at a lower amplitude. Two hypotheses are advanced to account for the changes in frequency of peak amplitude: a variable vocal tract resonance or “source generated” amplitude changes, and their relative merits are considered. The importance to the animals of high amplitude frequency sweeps is discussed, considering the conditions under which they are produced and whether the echoes from such pulses can be detected.
Genetically determined polymorphism of two peptidases in the Tuco‐tuco (Ctenomys talarum talarum)
Authors: Lewis W. H. P.
Published: August 2009

Six distinct peptidases have been found to occur in the erythrocytes of the Tuco‐tuco. The substrate specificities suggest that these enzymes are homologous with the peptidases previously described in man and the mouse. Common polymorphisms of two of this group of enzymes are described.
The syrinx in family Columbidae
Authors: Warner Robert W.
Published: August 2009

The pigeon syrinx is markedly different to that organ in most other birds, and although basically a simple structure, shows a number of unique modifications, the significance of which cannot readily be fully assessed. The tracheal rings are dorsally cartilaginous, but are thickened and ossified over their ventral surfaces; the sternotrachealis muscles are asymmetrically inserted on to the trachea. There is an extensive unsupported area in the external walls of the syrinx, resembling an external tympaniform membrane, but which does not appear to be a sound source. The tracheolateralis muscles insert directly on to this area, not on to the adjacent rings. There is no rigid pessulus.

The sound‐producing mechanism of the Columbidae is different to that found in other non‐passerine birds. The anatomy of the syrinx is described in detail, and the mechanism of sound‐production is discussed.
Seasonal changes in the copper content of the liver of the Common shrew, Sorex araneus over a two‐year period
Authors: Hyvärinen H.
Published: August 2009

Seasonal changes in the liver copper content of the common shrew were measured over two years. The copper content increased rapidly in autumn; in one year the levels remained high until the Spring, but the following winter there was a sharp decrease after December. It is suggested that differences in liver copper content are connected with differences in the metabolic steady state caused by differing environmental conditions in the two winters.
An interpretation of morphometric and gravimetric differences shown by adult Steganacarus magnus (Acari: Cryptostigmata)
Authors: Elmes G. W. , Webb N. R.
Published: August 2009

The weights and lengths of about a thousand individuals of Steganacarus magnus (Nic.) have been analysed and found to have a bimodal distribution. It is suggested that this can be used as an aid to separating the sexes in this species.

An analysis of the weight distributions of adult Steganacarus magnus (Nic.) showed them to be bimodal. Small individuals, without eggs and pre‐larvae had a mean weight of 159 μg and large individuals with eggs and pre‐larvae had a mean weight of 335 μg. It is suggested that these two weight classes represent male and female individuals.
A study of the internal parasites of small rodents from woodland areas in Surrey
Authors: Lewis J. W. , Twigg G. I.
Published: August 2009

The occurrence of helminth parasites and leptospires from the Long‐tailed field mouse, Apodemus sylvaticus, the Bank vole, Clethrionomys giareolus and the Short‐tailed vole, Microtus agrestis has been studied from four woodland areas in Surrey. The composition of the helminth fauna of these rodents, particularly A. sylvaticus and C. giareolus, differs from that of previous studies carried out in the British Isles in consisting largely of cestodes and fewer species of digeneans and nematodes. On the other hand the degree of infection of the rodents with nematodes as in the case of A. sylvaticus infected with the trichostrongylid Nematospiroides dubius and theoxyurid Syphacia stroma and of C. giareolus with thecap‐illarid Capillaria muris sylvatici is greater than the cestode and digenean infections and is probably linked with the monoxenous nature of the nematode life cycles.

Differences in the number, incidence and degree of infection of mice and voles with species of helminths is undoubtedly linked with differences in the feeding habits of the respective hosts but the present study has also confirmed that infection levels in both leptospires and helminths are influenced by the age/sex relationships of the host together with season and habitat. The relationship between the distribution of rodents infected with leptospires and some helminths suggests similarities in the mode of their transmission.
Allometric growth in two species of Ectobius (Dictyoptera: Blattidae)
Authors: Brown Valerie , Davies R. G.
Published: August 2009

Allometric growth of the postembryonic stages of Ectobius lapponicus (Linn.) and E. panzeri Stephens is described and analysed. Alternative methods of computing the allometric growth equation are discussed and applied, with the necessary significance tests, to a large number of skeletal structures in all developmental stages of each sex. The validity of Dyar's Law and its modifications are assessed quantitatively.

The growth in linear dimensions of 74 exosketetal structures has been studied quantitatively in all instars of both sexes of Ectobius lapponicus and E. panzeri.

Almost all the investigated structures show some statistically significant degree of allometric growth, but relatively few of them grow by simple allometry. Some possible reasons for this are indicated.

Well‐defined growth gradients exist in the appendages and along the main axis of the body. Allometric growth contours, showing sexual and specific differences, express the temporal and spatial variations in the allometric growth ratio.

The limitations of Dyar's Law and Przibram's Rule are discussed and it is shown that conformity with Dyar's Law is not improved by allowing for differences in the duration of the instars.

It is emphasized that allometric growth studies should involve the choice of a suitable reference dimension and the selection of an appropriate statistical model to which the growth data are fitted. The estimation of the allometry parameters a and b, as well as the appropriate significance tests, depend on the model chosen, though the two models compared in this study do not yield appreciably different estimates.
Some effects of X‐irradiation on the activity of the thyroid and pituitary glands of Xenopus laevis (Amphibia) during metamorphosis
Authors: Chopra D. P. , Hamilton Louie
Published: August 2009

A histological study of irradiated thyroid and pituitary glands of metamorphosing Xenopus tadpoles was made. Both glands shrink, reaching a minimum nine hours after irradiation and recover by 24 hours. It is suggested that sudden release of hormones may explain a reported hastening of metamorphosis in irradiated tadpoles.

Xenopus larvae received 2500 rads of whole body X‐rays.

Nine hours after irradiation both pituitary and thyroid volumes were significantly less than the controls. From 24 hours after, the volumes had returned to control levels.

The mitotic incidence in irradiated thyroids fell within five hours to one tenth of the control value and remained suppressed for at least three days.
Haplodrassus umbratilis, a gnaphosid spider new to Britain, from the New Forest
Authors: Merrett P.
Published: August 2009

Both sexes of Haplodrassus umbratilis (L. Koch) are described and figured from material collected in the New Forest, Hampshire. Some comments on its habitat and phenology, and a list of other spiders found in the locality, are also given.
A comparative study of territory in the Reed warbler (Acrocephalus scirpaceus) and Sedge warbler (A. schoenobaenus)
Authors: Catchpole C. K.
Published: August 2009

Various aspects of territoriality were studied comparatively in a marked population of Reed and Sedge warblers at the Attenborough Nature Reserve, Nottinghamshire. Differences in arrival patterns, establishment of territory and particularly territory size were detected. In view of the dynamic nature of territory boundaries, a method is described for obtaining measures of mean territory size for comparative purposes. The sympatric species were largely separated by different breeding and feeding habitats, but there was also a degree of interspecific competition in some areas and interspecific territorialism was found to occur. Adults of both these migratory species were found to exhibit strong site fidelity, and there was some evidence to suggest that early post‐fledging experience may influence initial selection of a particular area and territory for first breeding.

The adaptive significance of territory is discussed in relation to the findings presented and current hypotheses. There was some evidence which suggests that reduction of predation pressure and intraspecific interference through spacing out, as well as provision of a nest‐site may be important functions of territory in these species, but no evidence that food supply or population regulation are involved. The significance of interspecific territorialism is considered in relation to interspecific competition. The various factors effecting territory size and the patterns of nesting dispersion are also considered in an attempt to account for the striking interspecific differences found between these closely related species. It is concluded that although a multiplicity of factors may well be interacting in complex fashion, the more important of these stem from contrasts in the physical properties of the two habitats.
Fine structure of the respiratory organs of the Climbing perch, Anabas testudineus (Pisces: Anabantidae)
Authors: Hughes G. M. , Munshi J. S. Dutta
Published: August 2009

An electron microscopic study has been made of the three respiratory organs of climbing perch. The gill structure is similar to that of the other telcosts but the thickness of the water/blood barrier is much greater, being as great as 20 μm in some specimens. The increased thickness is due to a multilayered epithelium which is thinner (3.5–7 μm) over the marginal channel of the secondary lamellae. The other two main layers, basement membrane and pillar cell flange, are relatively thin (about 1 μm).

The pillar cells have a typical structure, but in certain regions they are contiguous with one another and line well‐defined blood channels. Some of the columns of basement membrane material in such regions may be common to adjacent pillar cells.

The air‐breathing organs are (a) the lining of the suprabranchial chambers, and (b) the labyrinthine plates attached to the dorsal region of branchial arches. Electron microscopy showed that their structure is well adapted for gas exchange, the air/blood barriers being only 0.12–0.3 μm, comprising an epithelial layer, basement membrane, and thin capillary endothelium. The many parallel blood channels of the respiratory islets of both organs are separated by pillar‐like structures which differ from the pillar cells of the secondary lamellae. Thus the hypothesis that the air‐breathing organs represent modified gills is not supported by this study.

The fine structure of the non‐respiratory region of the air‐breathing organs is similar to that of the skin, and includes chemoreceptor‐like cells. Evidence concerning the possible homology of pillar cells with plain muscle cells is discussed.
Ecological studies on crater lakes in West Cameroon The blood of endemic cichlids in Barombi Mbo in relation to stratification and their feeding habits
Authors: Green J. , Corbet Sarah A. , Betney Elaine
Published: August 2009

The West Cameroonian crater lake Barombi Mbo is stratified, with no detectable oxygen below 20 m. Of the endemic cichlid fishes in this lake Konia dikume is exceptional in having a mean haemoglobin concentration of 16.55 g/100 ml, while the other ten endemic cichlids range from 5.55 to 8.70 g/100 ml blood. The erythrocyte count is also higher in K. dikume than in the other species.

The phytoplankton in the lake is most abundant between 10 and 15 m from the surface.

The single species of cyclopoid copepod and the rotifers in the zooplankton remain in the top 20 m throughout the day and night, but the larvae of Chaoborus spend the daytime at depths below 20 m, mostly between 30 and 70 m. At night these larvae ascend into the upper layers, and feed on rotifers.

Konia dikume feeds on the larvae of Chaoborus, and the high concentration of haemoglobin in the blood of this fish, coupled with a large blood volume, appears to be an adaptation for the storage of oxygen. This would enable the fish to dive into the deoxygenated hypolimnion and extend the time available for feeding when the Chuoborus larvae are ascending at dusk and descending at dawn. Konia dikume appears to be a visual feeder, and in the short tropical twilight any extension of the feeding period could be of survival value.
Spermatophore formation in the pseudoscorpion Chthonius ischnocheles (Chthoniidae)
Authors: Legg G.
Published: August 2009

The reproduction of pseudoscorpions involves indirect sperm transfer by means of spermatophores. The spermatophores are the product of the male genital atrium. A functional interpretation of spermatophore formation in Chthonius ischnocheles is based on evidence from (a) a morphological study of the genital atrium, the associated accessory glands and the musculature (b) males sectioned during spermatophore production (c) histochemical tests on the glands and their secretions (d) biochemical analyses of one gland (posterior dorsal) and its secretion (e) the behaviour of males during this process and (f) the structure of the spermatophore.

The anterior region of the genital atrium is concerned with the production of the sperm packet. The encysted sperm and the seminal fluid from the prostatic reservoir are encapsulated in a sperm packet by a secretion from two pairs of anterior glands. The posterior region of the genital atrium is responsible for the formation of the spermatophore stalk and its distal elaboration, the two lateral collars. These parts of the spermatophore arise from the fibroin secretion of the posterior dorsal gland; the shape of the spermatophore collars is correlated with their mould, the medial diverticula. In addition the lateral glands secrete a light oil which accumulates on a thickening of the spermatophore stalk proximal to the collars. This suggested that this secretion acts as a pheromone to attract females to the spermatophore since in this species males produce their spermatophores in the absence of females.