bluuebunny/crossref_metadata_2025 huggingface dataset:
An appropriate physiological control for environmental temperature studies: comparative growth kinetics of winter rye
Authors: Krol M. , Griffith M. , Huner N. P. A.
Published: August 2008

The accurate interpretation of physiological and biochemical alterations observed in plants grown under contrasting environmental conditions requires knowledge of their relative physiological ages. For this purpose, we compared the growth kinetics of winter rye (Secale cereale L. cv. Puma) at nonhardening and cold-hardening temperatures. Growth at nonhardening temperatures was characterized by a 10-day lag phase with the attainment of maximum growth after about 28 days. Growth at cold-hardening temperatures resulted in an extension of the lag phase to about 21 days with maximum growth being attained after 56 days. The calculated growth coefficient at cold-hardening temperatures was 35–40% of that at nonhardening temperatures. This relationship was consistent with growth parameters such as leaf dry weight, fresh weight, and area, but not with plant height. Although total leaf dry weight and total number of leaves per plant did not differ between nonhardened and cold-hardened plants at maximum growth, total leaf area per plant and stretched plant height was 3- to 4-times greater in nonhardened than in cold-hardened plants. This resulted in a fourfold increase in leaf dry weight per leaf area during growth at low temperature in contrast to the maintenance of a constant ratio during growth at nonhardening conditions. The increase in this ratio during low temperature growth was, in part, accounted for by a decrease in water content and an increase in cytoplasmic content. These results were confirmed by the investigation of growth on an individual leaf basis. However, the growth response of leaves 1 and 2 differed from that of leaves 3 and 4 when the leaf dry weight: leaf area ratio was measured as a function of time at cold-hardening temperatures. This indicates that the stage of leaf development influences its growth response to an altered environment. The results of the development of leaf freezing tolerance indicated that maximum vegetative growth appeared to coincide with maximum freezing tolerance of leaves from cold-hardened plants (−22 °C) but not of leaves from unhardened plants (−11 °C).
Revision of Torula species. A new combination for Torula quaternata
Authors: Schoknecht Jean D. , Crane J. L.
Published: August 2008

The general morphology and conidial development of Torula quaternata are characteristic of the genus Tretospora Ellis and a new combination in that genus is proposed.
Influences of Anadromous Spawning Behavior and Optimal Environmental Conditions Upon Striped Bass (Morone saxatilis) Year-Class Success
Authors: Ulanowicz R. E. , Polgar T. T.
Published: August 2008

An analysis of the spatial and temporal abundance patterns of developing striped bass (Morone saxatilis) ichthyoplankton stages in the Potomac Estuary, including a Markovian description of transport, indicates that annual differences in the distribution of spawning fish are not likely to account wholly for the wide fluctuations in year-class success. Year-class success can be decomposed into the product of two factors — one extrinsic, acting upon the eggs and larvae, and the other, a behavioral property of the adult stock. The effect of extrinsic environmental conditions upon year-class success can be measured relative to the maximum computed survival of eggs to post-finfold larvae among all locations and times during a given year. Apparently, the behavior of the spawning adult fish is not well matched with the environmental conditions favorable to ichthyoplankton survival, and therefore, the actual spawning distribution yields only a fraction (the spawning fitness) of the maximum production possible during that year. Spawning fitnesses were estimated to be small (< 0.02 out of 1.0) and varied by less than a factor of two over the three seasons observed. In contrast, the year-class success as measured by post-finfold production differed 35-fold over the same 3 yr. It appears most likely that the large range in success is due primarily to the extrinsic, density-independent environmental factors which determine the optimum survivals in combination with spawning behavior. However, no strong case can be made for behavioral compensation by spawning fish to offset changes in the annual optimum survival conditions for ichthyoplankton.Key words: anadromous, ichthyoplankton development, Markovian transition probabilities, optimal survival, spawning behavior, spawning fitness, striped bass, transport model, year-class success
Effects of Dietary Ascorbic Acid on Chronic Lead Toxicity to Young Rainbow Trout (Salmo gairdneri)
Authors: Hodson P. V. , Hilton J. W. , Blunt B. R. , Slinger S. J.
Published: August 2008

Newly hatched rainbow trout (Salmo gairdneri) exposed to waterborne lead and receiving diets deficient in, or supplemented with, ascorbic acid, developed classical symptoms of lead toxicity and ascorbic acid deficiency. Those exposed to lead showed elevated blood lead concentrations, inhibition of erythrocyte δ-amino levulinic acid dehydratase, darkening of the tail regions and spinal curvatures. Those receiving ascorbate deficient diets showed depletion of carcass, liver, kidney, and brain ascorbic acid concentrations plus spinal curvatures. Fish subjected to both treatments simultaneously showed no evidence of an enhancement of ascorbate deficiency symptoms by exposure to lead or enhancement or reduction of lead toxicity symptoms by ascorbate deficient or supplemented diets, respectively. These results demonstrate that, although aspects of lead toxicity in fish resemble ascorbic acid deficiency, there is no metabolic interaction between the two factors.Key words: pollutants, toxicity, interaction, lead, vitamin deficiencies, Salmonidae, rainbow trout
Feeding Ecology and Vertical Migration of Adult Alewives (Alosa pseudoharengus) in Lake Michigan
Authors: Janssen John , Brandt Stephen B.
Published: August 2008

Vertical distributions of adult alewife (135–216 mm long) and Mysis relicta were measured acoustically on a 24 h basis during July, September, and October 1975 and June 1976 at a station 8 km northeast of Milwaukee, Wisconsin in 50 m of water. Both Mysis and adult alewife concentrated on the bottom during day and migrated upwards to the base of the thermocline at night. Extent and timing of vertical migrations of Mysis and alewife coincided. During bright moonlight Mysis concentrated at depths well below the thermocline and larger adult alewives concentrated within this Mysis layer while smaller adult alewives migrated to the base of the thermocline. An examination of stomach contents indicated that vertical migrations were mechanistically linked to feeding behavior. Adult alewives fed extensively on Mysis at night. Total lengths of Mysis in alewife stomachs were significantly longer than total lengths of Mysis captured in vertical plankton tows. Pontoporeia hoyi occurred in alewife stomachs in late afternoon (September) and early evening (June, October). Microcrustacean zooplankton were eaten mostly during day (June) or early morning (October). As Mysis was the most important food, the vertical migration of alewives is interpreted as an adaptation for feeding on vertically migrating Mysis.Key words: alewives, Lake Michigan, Mysis, Pontoporeia hoyi, vertical migration, feeding ecology, light
Interactive Effects of Geophysically-Forced Sea Temperatures and Prey Abundance on Mesoscale Coastal Distributions of a Marine Predator, Atlantic Cod (Gadus morhua)
Authors: Rose G. A. , Leggett W. C.
Published: August 2008

Geophysically-forced sea temperatures and prey abundance interactively regulated mesoscale (10's to 100's of km) inshore Atlantic Cod (Gadus morhua) distribution patterns in the northeastern Gulf of St. Lawrence, in both 1985 and 1986. Cod were located most often at temperatures within the range 0–5 °C. However, when mean densities of their chief prey (capelin, Mallotus villosus) were high (> 100/105m3) within the coastal zone, cod frequented waters having temperatures similar to those at which this prey were aggregated, within the broader range of temperatures −0.5 to 8.5 °C. The proportions of cod occupying sea temperature strata were significantly and positively correlated with those of capelin (r = 0.64, slope = 0.6, df = 86), in both 1985 and 1986, under two conditions: (1) sea temperatures within the range 1–9 °C; and (2) mean capelin densities > 100/105m3. Under conditions of lower mean capelin densities, cod distributions were independent of those of capelin. At temperatures outside the range 1–9 °C, cod and capelin densities were not correlated, regardless of capelin densities.
Siliceous Microfossil Succession in the Sediments of McLeod Bay, Great Slave Lake, Northwest Territories
Authors: Stoermer Eugene F. , Schelske Claire L. , Wolin Julie A.
Published: August 2008

Quantitative analysis of biogenic silica and siliceous microfossils preserved in sediments of McLeod Bay, Great Slave Lake, NWT, Canada, shows increased abundance and modified species composition in more recent sediments. Most of the observed increase has apparently occurred in the post-industrial era. Although McLeod Bay remains highly oligotrophic, increased microfossil flux and changes in species composition indicate increasing nutrient supply. Since there is little apparent anthropogenic modification of the bay's drainage basin or biotic communities, atmospheric transport of nutrients from remote sources may be implicated.
Fish Production Correlated with Primary Productivity, not the Morphoedaphic Index
Authors: Downing John A. , Plante Céline , Lalonde Sophie
Published: August 2008

Estimates of the biological production of entire lake fish communities were collected from the published literature on lakes covering a wide range of geographic areas and trophic status. Correlation analysis shows that fish production is uncorrected with the morphoedaphic index (p > 0.05) but closely correlated with annual phytoplankton production (r2 = 0.79), mean total phosphorus concentration (r2 = 0.67), and annual average fish standing stock (r2 = 0.67). Empirically derived regression equations are presented and compared with previous models based on catch and yield data. Analysis of these equations suggests that conversion of phytoplankton into fish production is 100 times more efficient in oligotrophic lakes than hyper-eutrophic ones, but that a much lower fraction of fish production can be channeled to sustainable yield in oligotrophic lakes. Sustained yields were frequently as little as 10% of the annual community fish production.
Benthos Response to Disturbance in Western Lake Erie: Field Experiments
Authors: Soster Frederick M. , McCall Peter L.
Published: August 2008

Open space (defaunated sediment) was provided on the floor of Lake Erie on 11 occasions during different seasons over a 26-mo period. The benthic community that developed was sampled over time and compared with the nearby undisturbed bottom community. A consistent succession of functional and adaptive types was observed. Early colonizers — the ostracod Physocypria globula, the naidid oligochaete Vejdovskyella intermedia, and the chironomid, Chironomus plumosus — exceeded their natural bottom abundances by 2–7 × within 40 d, but decreased in abundance later. They are small and mobile, live and feed close to the sediment–water interface, and reproduce often. Late colonizers — Limnodrilus spp., Ilyodrilus templetoni, and pisidiid bivalves — reached natural abundances only after several months if at all. They are large, deep infaunal dwellers that grow slowly and reproduce late in life. An intermediate group — Arcteonais lomondi, Specaria josinae, Pristina acuminata, Dero digitata, Procladius sp., and Coelotanypus sp. — reached their natural abundances early but did not exceed them. This successional sequence of functional and adaptive types appears to be a general response by both shallow freshwater sublittoral and shallow marine subtidal macrofauna to space-providing disturbances despite radical taxonomic dissimilarity.
Food Chain Structure in Ontario Lakes Determines PCB Levels in Lake Trout (Salvelinus namaycush) and Other Pelagic Fish
Authors: Rasmussen J. B. , Rowan D. J. , Lean D. R. S. , Carey J. H.
Published: August 2008

The trophic structure of pelagic communities in lakes of glaciated regions is highly variable due to restricted dispersal of glacial relict taxa and recent species introductions. Much of the enormous between-lake variability in PCB levels in lake trout flesh (15–10 000 ng/g) from the St. Lawrence system results from differences in the length of pelagic food chains. Ontario Ministry of the Environment data (1978–81) on PCB concentrations in lake trout flesh indicate that PCB concentrations increased with the length of the food chain and tissue lipid content, and decreased with distance north of urban-industrial centres. Each trophic level contributed about a 3.5-fold biomagnification factor to the PCB concentrations in the trout, and the lipid content of the trout flesh increased by a factor of 1.5 for each additional trophic level. An empirical model capable of predicting PCB levels in pelagic salmonids and forage fish (smelt and coregonids) indicated that biomagnification of small atmospheric inputs of persistent lipophilic contaminants can explain the frequent occurrence of high levels of contaminants in some biota from remote areas, and that species introductions that lengthen food chains will lead to significant increases in levels of atmospherically dispersed persistent organic contaminants in top predators.
Hybridization with Domesticated Rainbow Trout (Oncorhynchus mykiss) Reduces Seasonal Variation in Growth of Steelhead Trout (O. mykiss)
Authors: Johnsson Jörgen I. , Clarke W. Craig , Withler Ruth E.
Published: August 2008

We tested the hypothesis that hybridization with domesticated rainbow trout (Oncorhynchus mykiss) reduces the seasonal variation in growth in both fresh and salt water in anadromous steelhead trout (O. mykiss). The seasonal variation in freshwater growth was more pronounced in the steelhead trout than in the hybrid and domesticated trout. Consequently, differences in growth rate among groups were considerably higher during winter than in fall or spring. We suggest that high feeding activity during unfavourable winter conditions in natural waters is maladaptive, but is not selected against in protected hatchery environments with a continuous food supply. This may lead to genetic divergence in feeding physiology and/or behaviour between steelhead trout and domesticated rainbow trout. Growth rates in experimental groups transferred to seawater in December relative to groups transferred in April were faster in rainbow and hybrid trout than in steelhead trout. The results support the hypothesis that seasonal variation in seawater growth in steelhead trout is reduced by crossing with domesticated rainbow trout.
Winds and the Demic Structure of a Population of Yellow Perch (Perca flavescens)
Authors: Aalto S. K. , Newsome G. E.
Published: August 2008

Variations in year-class strengths of populations of fish are often attributed to environmental effects such as wind or temperature. Previously, we have presented evidence showing that the yellow perch (Perca flavescens) in a lake are composed of demes or subpopulations that vary independently. Here, we explore the relationship between winds from different directions and the independent variations of the demes of yellow perch in the study lake. We present a model that includes an instantaneous rate of mortality due to winds during the embryonic stage of yellow perch. The variables used to explain the observed egg-mass counts and thus the variations in the size of the demes are lagged egg-mass counts and winds, each of which varies yearly. Using wind and egg-mass census data, we were able to find statistically significant models that explain much of the variation (52–61%) in the independently varying demes (four of six investigated) of yellow perch in our study lake. We also present data that show that water temperatures vary in different ways at different sites in the same year, and in different ways at the same site in different years.
Brown Trout (Salmo trutta) Status and Chemistry from the Norwegian Thousand Lake Survey: Statistical Analysis
Authors: Bulger Arthur J. , Lien Leif , Cosby B. J. , Henriksen Arne
Published: August 2008

Substantial negative impacts of acidic precipitation on freshwater fishes have been recorded over the last 50 yr in Norway. We analyzed the present status and historical trends of brown trout (Salmo trutta) populations in relation to water chemistry in 584 Norwegian lakes. Since the 1940s, 39% of the lakes have lost their trout populations, and another 17% of the lakes have declining trout populations; thus, 56% of the populations have been adversely affected. The results of analysis of variance, principal components analysis, and discriminant analyses converge on the variables pH, monomeric inorganic aluminum, and alkalinity as most strongly related to trout status. Lakes whose trout populations are extinct have an average aluminum concentration of 133 μg/L, an alkalinity of −34 μeq/L, and a pH of 4.8 versus 11 μg Al/L, + 27 μeq/L, and 6.0 for lakes with healthy populations. Also, nitrate and sulfate levels are significantly higher in affected versus unaffected lakes. Calcium and sulfate appear to influence trout status moderately as individual variables, but strongly in combination, since they are the major determinants of alkalinity in these lakes. Models based on discriminant analyses showed good success (up to 89%) in predicting trout population status categories from water chemistry.
Influence of Environmental Variation and Spawning Stock Levels on Recruitment of Ocean Shrimp (Pandalus Jordani)
Authors: Hannah Robert W.
Published: August 2008

The influence of environmental factors on recruitment variability in ocean shrimp (Pandalus jordani Rathbun) from 1967 to 1988 was investigated using correlation and multiple regression. Low sea levels during larval release in April, indicative of a strong spring transition in coastal currents, were strongly correlated with increased recruitment. Interannual changes in catch distribution showed an interaction between shrimp abundance and distribution, with reduced catches accompanying a northerly catch distribution. A linear model incorporating April sea level explained 58% of the variation in log recruitment and also correctly indicated a serious year class failure in 1989. An index of spawning stock was compared with the residuals from the linear model based on April sea level, but no stock–recruitment relationship was found.
Fish Species Composition and Lake Abiotic Variables in Relation to the Abundance and Size Structure of Cladoceran Zooplankton
Authors: Rodríguez Marco A. , Magnan Pierre , Lacasse Sylvain
Published: August 2008

Redundancy analysis and a multiple regression approach to analysis of variance and analysis of covariance were used to evaluate the influence of fish species composition and abiotic variables on the numerical density, biomass, and mean length of individual cladoceran taxa from 43 Laurentian Shield lakes. Cladoceran assemblage structure was still associated with fish species composition when potentially confounding effects of abiotic variables were accounted for by partial redundancy analysis. Cladoceran abundances were strongly related to the occurrence of white sucker (Catostomus commersoni) and lake maximum depth; mean lengths were influenced most by white sucker, water transparency, lake volume, and sampling date. The abundance of bosminids and length of Holopedium were strongly related to the occurrence of white sucker even when the influence of abiotic factors was removed by regression. In lakes with white sucker and brook trout (Salvelinus fontinalis), Holopedium mean length decreased and bosminid abundance increased fourfold relative to lakes with brook trout only; large (>1.2 mm) Holopedium abundance was reduced by 76–81%, suggesting that size-selective predation occurred. The increase in bosminid abundance in the presence of white sucker may have been a response to diminished competition by large Holopedium, but density compensation was not observed.
A reconsideration of forms of squid of the genus Illex (Illicinae, Ommastrephidae). II. Sexual dimorphism
Authors: Mangold (nee Wirz) Katharina , Lu C. C. , Aldrich Frederick A.
Published: August 2008

Samples of 382 males and 351 females of the ommastrephid squid of the genus Illex from the Mediterranean, and 452 males and 457 females from Newfoundland coastal waters were compared on the basis of selected morphological criteria, based on individuals of comparable size. It is evident that the form characteristic of the Mediterranean (Illex illecebrosus coindetii (Verany, 1837)) demonstrates strongly developed morphometric sexual dimorphism. Such is not the case with the Newfoundland form (Illex illecebrosus illecebrosus (Lesueur, 1821)).
Morphology and histology of the cephalic endocrine glands of the damselfly, Coenagrion angulatum Walker (Zygoptera: Odonata)
Authors: Gillott C.
Published: August 2008

In Coenagrion angulatum Walk. there is a single group of neurosecretory cells, median in position, on each side of the brain. The A- and B-type cells are intermingled within each group and their axons form a single pair of nerves to the corpora cardiaca. No pattern of secretory activity is discernible in the B cells. The A cells of mature nymphs and newly emerged adults are loaded with fuchsinophilic droplets but the amount of stainable material decreases as sexual maturation proceeds. A corresponding change in the location and amount of fuchsinophilic material takes place in the corpora cardiaca. In the mature nymph and young adult there is much material distributed throughout the gland. During sexual maturation it becomes less in quantity and restricted to a position adjacent to the aorta wall. A pair of stout, strongly fuchsinophilic nerves leaves the anterior end of the corpora cardiaca and passes ventrolaterally. These bypass the corpora allata and enter the thorax. Their point of termination has not been determined in this study. The corpora allata are small, roundish-oval bodies in the mature juvenile and newly emerged adult damselfly. While retaining their general shape they increase in volume several fold as sexual maturation takes place. The ventral glands are large, lobular structures in mature nymphs. Immediately after emergence they shrink and their cells become pycnotic. Generally by the fourth day of adult life they have disappeared. The results of this study are discussed in relation to those of other authors for the Odonata.
Proprioceptors in the gills of teleosts
Authors: Sutterlin A. M. , Saunders R. L.
Published: August 2008

Two groups of proprioceptors were found on the gills of the sea raven and Atlantic salmon. Receptors associated with the gill filaments respond to filament displacement and receptors located in the region of the gill rakers respond to displacement of the rakers. Branchial divisions of cranial nerves IX and X innervating the different gills contain both classes of receptor fibers. The size and properties of the receptive fields are described and possible physiological functions for the receptors are proposed.
The embryonic behavior of the mysid shrimp, Mysis relicta
Authors: Berrill Michael
Published: August 2008

The various activities of the embryos of the relict mysid, Mysis relicta, develop into the swimming, feeding, avoidance behavior, and continuous heartbeat of the newly hatched individuals. Several of the embryonic activities are rhythmically organized, and these rhythms are age and temperature dependent. Moreover, reflex response to tactile stimulation is late in developing. The embryonic behavior is therefore integrated, apparently spontaneous, and possibly neurogenic, and bears much in common with some aspects of the development of behavior of vertebrate embryos.
Nematodes of the genus Tylenchorhynchus (Tylenchoidea:Nematoda) from the Canadian high Arctic
Authors: Mulvey R. H.
Published: August 2008

Three species belonging to the genus Tylenchorhynchus Cobb, 1913, including two new species, are recorded from the Canadian high Arctic. Tylenchorhynchus arcticus n. sp., T. parobscurus n. sp., and T. leptus Allen, 1955 are illustrated and described.
Erythropoiesis in chicken peripheral blood
Authors: Smith Natasha , Engelbert Vibeke E.
Published: August 2008

A form of erythropoiesis occurring in the peripheral blood of young domestic chickens which differs radically from descriptions in classical hematology has been demonstrated with several staining methods and modern methods of microscopy. New erythrocytes arise directly as nuclear buds from young mature erythrocytes. The new cell is a clone, as it were, of the mother cell and classical mitosis is not involved. Stages of progressive differentiation in clone cells terminate with the mature erythrocyte. The frequency of clone cells in peripheral blood ranges from 3.7% to 6.8%, in sharp contrast to the figure of 0.2% for mitosis that has been reported in the literature.
A descriptive analysis of the aggressive behavior of the male brook stickleback, Culaea inconstans
Authors: McKenzie Joseph A.
Published: August 2008

The agonistic responses of the male brook stickleback have been described. These displays do not follow or precede each other randomly. It is concluded that common causal factors are operating within the animal. Sequential analysis of these responses reveal that they can be related to states that vary between the tendency to attack and the tendency to flee. The fact that biting rarely occurs in territorial border encounters supports the theory that threat as a social signal evolved to accomplish spatial restriction without bodily injury.
Topography and vascularization of brown fat in a small nonhibernator (deer mouse, Peromyscus maniculatus)
Authors: Rauch Josefine C. , Hayward J. S.
Published: August 2008

Thirteen identifiable deposits of brown fat occur in the deer mouse, Peromyscus maniculatus. Drawings of these deposits and their vascular supply are presented. Blood vessels were distinguished during dissection by filling the circulatory system with methyl methacrylate. The findings show clearly the potential of brown fat to transfer heat efficiently to the blood during a situation of cold exposure of the mouse, thereby providing further evidence in support of a thermogenic role for this tissue.
Paronchocerca bumpae n. sp. from the brushland tinamou and the position of Paronchocerca within the Splendidofilariinae (Filarioidea)
Authors: Anderson Roy C. , Prestwood Annie K.
Published: August 2008

Paronchocerca bumpae n. sp. from the heart of Nothoprocta cinerascens (Tinamidae) of Argentina is most similar to P. straeleni but the latter species lacks a preanal median papilla, and has deirids and transverse bands of cuticular bosses on the ventral surface of the male caudal extremity. The genus Paronchocerca, reviewed and redefined herein, also contains ciconiarum, bambusicolae, helicina, mansoni, mirzai, papillata, rousseloti, and tonkinensis. P. choprai and P. sanquinis-ardea are regarded as species inquirendae. Paronchocerca is related to Cardiofilaria and Aproctella. The genera Paraprocta, Aproctoides, and Anenteronema (all monotypic) are considered of dubious status. Lerouxinema is considered a synonym of Chandlerella, resulting in the combination C. lerouxi (Singh, 1949) n. comb. Chandlerella pelecani (Chabaud and Rousselot, 1956) n. comb. is proposed for Striatofilaria pelecani. A key is given to the adequately defined genera of Splendidofilariinae known from birds.
Ionic and osmotic concentration of tears of the gull, Larus glaucescens
Authors: Hughes Maryanne Robinson
Published: August 2008

The osmotic pressure (O.P.) and ionic concentrations of sodium (Na), potassium (K), and chloride (Cl) ions were measured in the tears and plasma of gulls, Larus glaucescens, that were drinking fresh water and dilutions of seawater. Concentrations of Na and Cl in tears were generally between 170 and 190 meq/l; K concentration between 1 and 2 meq/l, and the osmotic pressure between 350 and 450 milliosmoles. In comparison with plasma, gull tears were hypertonic in Na and Cl, approximately isotonic in K, and always hyperosmotic. Neither the concentration of the drinking water nor removal of the salt glands affected ion concentrations, O.P. of tears, or the tear:plasma ratios of these factors.
The salivary glands of adult blackflies
Authors: Gosbee J. , Allen J. R. , West A. S.
Published: August 2008

Salivary glands of adult female blackflies of known ages were examined by histological methods. These studies showed that each of the paired salivary glands consists of two parts: a reservoir composed of relatively small cells, and a U-shaped lobe composed of larger secretory cells. The secretory cells progressively accumulate a PAS-positive secretory substance during the first 48 h of adult life. The PAS-positive material is lost from the secretory cells when the blackfly takes a blood meal. During the first 24 h after a blood meal the secretory cells again synthesize some PAS-positive material, but in some individuals the resynthesis is still not complete after 72 h. Limited examination of the salivary glands of males was carried out.
Studies of physiologically active arthropod secretions. III. Chemical, morphological, and histological studies of the defence mechanism of Uroblaniulus canadensis (Say) (Diplopoda:Julida)
Authors: Weatherston J. , Percy J. E.
Published: August 2008

The defensive secretion of a millipede, Uroblaniulus canadensis (Say), is shown to consist of a mixture of benzoquinones and aliphatic compounds. Two of the benzoquinones are identified as p-benzoquinone and 2,3-dimethoxybenzoquinone. The gross structure of the gland producing the secretion is described and histological studies reveal the presence of secretory units. Each secretory unit consists of a pair of specialized cells and has a tubule to transport the secretion manufactured in these cells to a large cuticular-lined reservoir.
Primary pulmonary involvement in rodents infected with Echinococcus multilocularis
Authors: Webster G. A. , Willett E. E.
Published: August 2008

Pulmonary cysts developed in four gerbils and one cotton rat infected orally with Alaskan strain Echinococcus multilocularis eggs. In three cases, liver and lung cysts were similar. Two rodents, however, showed typical fertile pulmonary cysts while the liver foci were small and sterile or necrotic. For these reasons, the lung infections were considered to be primary in origin.
Alaria arisaemoides Augustine and Uribe, 1927, (Strigeidae) from Interior Alaska
Authors: Compton Thomas L.
Published: August 2008

Seventeen adult Alaria arisaemoides Augustine and Uribe, 1927 were taken from the intestine of an adult red fox (Vulpes fulva) in Interior Alaska. This is the first record of A. arisaemoides in the boreal zone of the western hemisphere. Measurements of the Alaskan worms support the synonymy of A. oregonensis with A. arisaemoides suggested by Dubois, 1963.
Twin onchospheres and protoscoleces of Echinococcus granulosus
Authors: Webster G. A. , Cameron T. W. M.
Published: August 2008

Eggs containing two onchospheres of Echinococcus granulosus and protoscoleces with double bodies are recorded.
The postnatal development of the ductus epididymidis in the rabbit
Authors: Leeson C. Roland , Leeson Thomas S.
Published: August 2008

The postnatal development and differentiation of the rabbit epididymis have been described. At birth, all segments of the ductus are lined by a simple, low columnar epithelium. By 16 days postnatal, the surrounding mesenchyme has condensed to form a tunica propria around the ductus. Evidence of differentiation first is seen in the caput at 28 days and by 43 days the epithelium is pseudostratified. Stereocilia appear in the caput by 63 days and differentiation begins in the other segments at this time. By 112 days, differentiation is complete. In the testis, spermatogenic activity begins at 63 days and all tubules are active by 84 days but spermatozoa are present in tubules and lumen of the corpus only by 112 days.
Cytokinesis in the gonocysts of the drone honey bee (Apis mellifera L.)
Authors: MacKinnon E. A. , Basrur P. K.
Published: August 2008

Gonocyst growth in the drone honey bee (Apis mellifera, L.) is characterized by a series of mitoses in which cytokinesis is incomplete. After karyokinesis, the division products are reoriented in such a way that the cleavage furrow and spindle remnants point towards the cyst center. Throughout the larval period the cyst center contains depositions of spindle plaques with distinct microtubules and other cytoplasmic components which are associated with the furrowing membranes.Cleavage in the lining cells of the gonocysts is complete. The membranes are closely associated with fibrils and microtubules appear to abut directly on these membranes even in late stages of cytokinesis. In the gonial cells, the innermost regions of the membranes in the furrows are subtended by, but not closely associated with, accumulations of fibrillar material. It is suggested that incomplete cytokinesis in the gonial cells may be mediated by restricted movement of the furrows and that the loose association of fibrillar materials with the furrowing membranes may be indicative of aspects of this process.
The function of the ventral velum during gill irrigation in Rana catesbeiana
Authors: Gradwell Norman
Published: August 2008

The direct observation of the ventral velum in normally breathing tadpoles confirms earlier evidence for a valvular function of this structure during inspiration. The ventral velum also acts as a hydrofoil during expiration and as a mucus-secreting surface for the entrapment of suspended food particles.As the volume of water pumped per irrigation cycle is normally less than the maximum volume of the buccal cavity, it is unnecessary for the pharynx also to become filled with inspired water during the sinking of the buccal floor. Therefore the ventral velum's cyclic occlusion of the buccal cavity from the pharynx is no handicap to normal irrigation; on the contrary, it is a prerequisite for the efficiency of the pharyngeal pump.The dorsal velum does not participate in valvular activity, but deflects the respiratory current downward and inward to the gill cavity via gill clefts 2, 3, and 4. Therefore the strong flow pumped into the pharynx by buccal compression is prevented from impinging directly on the ciliated groove behind the dorsal velum and thereby interfering with the transport of food into the esophagus.
The distribution and behavior of Peromyscus maniculatus gracilis and Peromyscus leucopus noveboracensis (Rodentia: Cricetidae) in a southeastern Ontario woodlot
Authors: Smith Donald A. , Speller S. Wayne
Published: August 2008

P. m. gracilis and P. l. noveboracensis are sympatric in southeastern Ontario and some adjacent areas. Similar in appearance, food and breeding habits, and frequently cohabiting certain forests, they may occupy identical niches, contrary to the competitive exclusion principle. A 12-week summer live-trapping study in a woodlot containing upland, mixed, and cedar forest associations showed that although most of their population characteristics were similar, their local distributions, densities, and certain behaviors differed. Noveboracensis inhabited upland forest but avoided mixed and cedar forest associations apparently because suitable refuges were lacking. The less dense population of gracilis was ubiquitous; gracilis and noveboracensis cohabited the upland forest. On release from traps noveboracensis sometimes 'froze' before darting in a zigzag manner to nearby cover, and ran up trees significantly more than gracilis, which usually ran instantly, rapidly, and directly to a more distant ground refuge. Low densities of both species reduced competition for available food and refuges. This may have facilitated cohabitation in the upland forest where differential use of ground- and tree-holes also contributed to reduction of competition and thus to compatibility. Coexistence may be transitory there; with denser populations, potential competition might be minimized by emigration of the more exploratory gracilis.
Temperature selection in day-old chickens (Gallus domesticus) and young japanese quail (C. coturnix japonicus)
Authors: Ogilvie David M.
Published: August 2008

Although laboratory studies of temperature selection have been conducted with a wide variety of organisms, few investigations of this phenomenon have yet been done with birds. In this study, day-old chickens showed a precise selection response when tested in a gradient of surface temperature ranging from about 4 to 56 °C. The mean temperature selected by 10 birds was 41.3 °C, a value which appears to approximate normal adult body temperature. Temperature selection was also demonstrated with Japanese quail of ages 1 to 2, 6 to 8, and 13 to 15 days, with mean selected temperatures of 44.3, 37.8, and 35.1 °C respectively. This decrease in the level of selected temperature with age is similar to that observed in small mammals.
Life cycle of Diaptomus oregonensis Lilljeborg in Sunfish Lake, Ontario
Authors: Lai H. C. , Carter J. C. H.
Published: August 2008

The life cycle of Diaptomus oregonensis in a partially meromictic lake was investigated during 1966–68. Three annual generations were produced in each of 1967 and 1968 when conditions were optimal. In 1966 no third generation appeared and D. oregonensis vanished in September, presumably after depositing resting eggs. Food scarcity is suggested as the cause of both slow summer development and production of resting eggs.
Haemolymph and ovarial proteins in the bark beetle, Dendroctonus pseudotsugae in relation to ovarian development
Authors: Sahota T. S.
Published: August 2008

Female-specific proteins appear in the blood of Dendroctonus pseudotsugae within 24 h of attack on the host logs. By 48 h these proteins reach their maximum concentration and form about 50% of the total blood proteins. Of the 2.5-fold increase in the concentration of blood proteins during this time, nearly 80% is accounted for by the female-specific proteins. These proteins start appearing in the ovaries 48 h after the attack on host material. The lag between the appearance of these proteins in the haemolymph and their incorporation into the developing ovaries is probably attributable to physiological incompetence of developing oocytes to incorporate these proteins in the early stages of their maturation.
The trypanosomes of Ranidae. II. The effects of excitation and adrenalin on the peripheral parasitaemia in the bullfrog (Rana catesbeiana Shaw)
Authors: Bardsley J. E. , Harmsen R.
Published: August 2008

The extent of the peripheral parasitaemia of the Trypanosoma rotatorium complex in bullfrogs (Rana catesbeiana Shaw) is subject to fluctuations depending on the metabolic state of the host. Electrical stimulation causes a significant increase in the peripheral haemoflagellate levels. Moreover, injections of adrenalin chloride solution result in a similar response, while injections of acetylcholine and hypertensin do not. Adrenalin may act directly on the trypanosomes or indirectly via the host through such phenomena as elevated glucose levels. Blood pressure does not appear to be a factor.
Marionina charae, a new species of enchytraeid (Oligochaeta) from the Canadian arctic
Authors: Tynen Michael J.
Published: August 2008

Marionina charae n. sp. was collected from a stream flowing out of Char Lake, Comwallis Island, in the Northwest Territories of Canada. Thirteen species of Marionina have now been described from North America, and seven species of enchytraeid have been found in the North American arctic.
Spawning and reproductive morphology of Scolelepis squamata (Spionidae: Polychaeta)
Authors: Richards Susan L.
Published: August 2008

The adults of three populations of the spionid polychaete Scolelepis squamata were studied throughout a year in Barbados. From quantitative estimates of gametes and numbers of breeding animals, four statistically reliable outbursts of spawning were determined, each about 2 months apart, followed by a cessation of breeding activity from November till February. Spermatophores of this species were described for the first time; they occurred at each of the four spawning times.General observations on the ecology and reproductive morphology of this species were made. Two varieties of this species were found; their possible relation to the species in the literature was considered.
Psorobia castoris spec. nov. (Acarina: Psorergatidae), a new itch mite from the beaver, Castor canadensis
Authors: Kok Nico J. J. , Lukoschus Fritz S. , Clulow Frank V.
Published: August 2008

Psorobia castoris spec. nov. parasitic in epithelium of the external ear of Castor canadensis is described and figured in detail. Distinctive marks to other species of the genus Psorobia are tabulated.
Variation in ruminal nitrogen levels among some cervidae
Authors: Klein David R. , Schønheyder Fritz
Published: August 2008

Among black-tailed deer (Odocoileus hemionus sitkensis), roe deer (Capreolus capreolus), and reindeer (Rangifer tarandus), nitrogen levels in the contents of the rumen show consistent patterns of variation. Among deer of each species on the same range during the same season, the animal-derived nitrogen component of the rumen contents decreases as the vegetative nitrogen component increases. This inverse relationship may result from one, or more likely both, of the following causes. (1) The ability of the ruminant to maintain a fairly constant rumen environment to allow for its most efficient function. (2) An adaptability in these deer species to compensate for low nitrogen levels in the forage by recycling of nitrogen through the saliva and further conservation of ruminal nitrogen by recycling it through successive generations of microbial populations. The apparent ability to compensate for variations in forage nitrogen levels is limited when deer are on range of general poor quality or during fall and winter when forage nitrogen levels are reduced.
Isolation of bacteria from the intestines of the mouse pinworms and from their host
Authors: Dunning E. M. , Wright K. A.
Published: August 2008

Bacteria were isolated from homogenates of Syphacea obvelata and Aspicularis tetraptera and from their habitats, the caecum and colon respectively, of mice. The bacterial flora isolated from both pinworms consisted of fewer species of bacteria than did the flora isolated from their respective environments. Only two species of bacteria were isolated from A. tetraptera while five were isolated from S. obvelata.
The presence of pteridines in the hypodermis as a taxonomic tool in crayfish
Authors: Waywell E. B. , Corey S.
Published: August 2008

The hypodermis of nine species of crayfish, Cambarus bartoni, Cambarus diogenes, Cambarus fodiens, Cambarus robustus, Orconectes immunis, Orconectes obscurus, Orconectes propinquus, Orconectes rusticus, and Orconectes virilis, Found in central and southern Ontario was examined by thin layer chromatography cellulose sheets for pteridines. Each species had a distinctive pattern. Evidence is presented to support the possibility that the occurrence of interspecific hybrids between O. propinquus and O. rusticus is more likely than between O. obscurus and O. propinquus. Sexual dimorphism is reported in O. propinquus. A pteridine which fluoresces yellow under ultraviolet light was specific to C. bartoni. A generic difference between the genera Cambarus and Orconectes was noted. This research suggests that xanthopterin, isoxanthopterin, sepiapterin, 2-amino-4-hydroxypteridine, and biopterin are present in these crayfish and that pteridines, in conjunction with other taxonomic criteria, can be used as species characteristics in systematic studies.
Anomalies in the position of lower teeth in the fisher, Martes pennanti Erxl. (Mammalia; Mustelidae)
Authors: Heráň Ivan
Published: August 2008

Probable pathological anomalies in the position of second and third premolars in the left lower jaw of the fisher are described.
A modification of Heidenhain's iron-haematoxylin technique, as used to stain smears of Drosophila larval polytene chromosomes and neuroblast cells
Authors: Moorman Albert E.
Published: August 2008

Acetic-acid-fixed smears of Drosophila larval salivary gland chromosomes and of neuroblast cells from the larval ganglion undergoing mitosis are prepared by a modification of Heidenhain's iron-haematoxylin technique, in which absolute methyl alcohol is the solvent of all reagents used in the staining process.
Dispersal and range expansion by the cardinal: an analysis of banding records
Authors: Dow Douglas D. , Scott D. M.
Published: August 2008

Patterns of dispersal by the cardinal, Richmondena cardinalis, a species that has been undergoing range expansion for over 70 years, were analyzed from banding data. About 13% of 1523 foreign retraps and recoveries were found outside the 10-min block of latitude and longitude in which they had been banded. Significantly more immatures than adults dispersed; sexual differences were not pronounced. Dispersal was more common among young birds, but was not restricted to first-year birds. More distant movements probably occur in the first year and mortality may be related to distance travelled. As cardinals become older, females may become more sedentary than males. Cardinals travelled greater distances between 1933 and 1942 than in any subsequent period, and the greatest increase in numbers dispersing occurred between 1953 and 1962. Range expansion has possibly resulted from shifts in general centers of dispersal, as banding recoveries do not suggest large-scale unidirectional movements. The relation of these results to published accounts of range expansion by the cardinal is discussed.
Ultrastructural localization of glycogen in the flight muscle of the blackfly, Simulium vittatum Zett.
Authors: Liu T. P. , Davies D. M.
Published: August 2008

Abundant glycogen was observed in flight muscles of newly emerged autogenous Simulium vittatum females. Much of the particulate glycogen is tightly packed in the sarcoplasm, but some is located within the myofibrils. More is found in I bands than in H bands. No glycogen was found in the flight muscle of 4-day-old flies.
The harp seal, Pagophilus groenlandicus (Erxleben, 1777). XIII. The gross and microscopic structure of the auditory meatus
Authors: Ramprashad F. , Corey S. , Ronald K.
Published: August 2008

The gross and microscopic structure of the auditory meatus of the harp seal (Pagophilus groenlandicus) is described from dissections and serial sections. The meatus bends ventrally from the oval external orifice, posteroventrally, ventrally, and finally medially into the cranium. The ventrally directed wall of the meatus is membranous, the posteroventral and ventrally directed wall is incompletely wrapped by cartilage, and the medially directed wall is bony. The areas between sections of the cartilaginous wall ate completed by connective tissue. The meatus is closed internally by the intrinsic helicis and antitragicus auricular muscles. The external orifice is closed by the superficial auricular muscles. The auditory meatus is lined with stratified squamous epithelium, sebaceous glands, and ceruminous glands. Longitudinal blood sinuses and elastic fibers in the hypodermis may function as a pressure regulating device during diving. Blood sinuses are most prominent in the bony region of the meatus and extend into the tympanic sulcus of the pars tensa. Blood sinuses engorged with blood and a closed meatus may enhance transmission of sound to the tympanic membrane when the seal is under water.
Tubifex newfei n.sp. (Oligochaeta, Tubificidae) with a preliminary reappraisal of the genus
Authors: Pickavance J. R. , Cook D. G.
Published: August 2008

Tubifex newfei n.sp. (Oligochaeta, Tubificidae) from Newfoundland is described. The worm shows affinities with both Tubifex and Peloscolex. As a result of this and other evidence some generic definitions within the Tubificinae are questioned, discussed, and it is concluded that the characters of the genitalia presently used to define these genera are inadequate.