Developmental Biology Commons^™

Características De La Osificación Craneal En Phyllomedusa Boliviana (Anura: Hylidae), Rafael O. De Sá, E. O. Lavilla

Biology Faculty Publications

RESUMEN. Dentro de la familia Hylidae disponemos de información sobre las secuencias de osificación craneal para menos del 4.0% de sus miembros. El presente trabajo describe la secuencia de osificación craneal de Phyllomedusa boliviana. El patrón general de osificación es similar a lo reportado para otras especies de la familia, pero existen algunas diferencias importantes tales como la osificación tardía de los próoticos y la osificación premetamórfica de neopalatino, vómer, cuadrado-yugal, pterigoides y columela. El lento desarrollo ulterior de la osificación resulta en juveniles con cráneos extensamente cartilaginosos.

ABSTRACT. Characteristics of the cranial ossification in Phyllomedusa …

Geographic And Nongeographic Variation In The Genus Microtus (Mammalia: Rodentia) In West Virginia, Tina M. Savage

Theses, Dissertations and Capstones

Geographic and nongeographic variation was assessed on 12 cranial and 4 external characters in approximately 400 specimens of Microtus (M. ochrogaster, M. chrotorrhinus, M. pinetorum, M. pennsylvanicus) in West Virginia. Univariate and multivariate statistical analyses were used to examine age-related variation, sexual dimorphism, elevation and geographic variation and litter size for each species of Microtus in the state. Cranial characters were more beneficial than external in detecting variation. Examination of data for each species of Microtus studied demonstrated that values and trends in variation is a specific rather than a generic trait. Age-related variation was present in some, …

The Development And Comparative Morphology Of The Mandibular Symphysis In Salamanders, Jennifer Lorenz Elwood

Biological Sciences Theses & Dissertations

Despite the extensive literature on salamander cranial morphology, few authors mention the structure or development of the mandibular symphysis. Adult specimens representing eight caudate families and larval Ambystoma opacum, representing nine developmental stages, were evaluated histologically to determine the structure and development of the mandibular symphysis.

From this analysis it was determined that early in the ontogeny of the mandibular symphysis Meckel's cartilages are separated by a band of undifferentiated cartilage. As development progresses, this band of undifferentiated cartilage gradually transforms into a wedge of fibrocartilage which fuses to Meckel's cartilages.

Symphyseal morphologies of the adult caudates could be broken …

Variation In Piglet Weights: Weight Gains In The First Days After Birth And Their Relationship With Later Performance, B. K. Thompson, D. Fraser

Ontogeny Collection

Piglets from 42 litters of Yorkshire sows were weighed 0, 1, 2, 3, 4, 5, 7, 10, and 14 d after farrowing in order to explore the highly variable weight gains during the first 2 wk after birth. All litters were adjusted to 10-12 piglets by fostering. Litters differed greatly in average gain per piglet during the first 3 d after farrowing, with litter means ranging from 5 to 227 g d‒1 per piglet for the 3-d period. Gains during days 0-3 tended to be somewhat lower if the sow had a high body temperature during these days, but the …

Use Of Water By Piglets In The First Days After Birth, David Fraser, P. A. Phillips, B. K. Thompson, W. B. Peeters

Ontogeny Collection

Use of drinking water was determined for 51 litters of piglets by weighing and refilling a water dispenser each day for the first 4 d after farrowing. Measures of spillage, evaporation, and piglet drinking behavior indicated that most disappearance of water represented actual drinking by the piglets. Water use varied greatly among litters with an average of 46 g d^‒1 per piglet over the 4 d, and a range of negligible use to about 200 g d^‒1. Water use, especially on day 2, was correlated negatively with the average weight gain of the litter during the first …

Variation In Piglet Weights: Development Of Within-Litter Variation Over A 5-Week Lactation And Effect Of Farrowing Crate Design, B. K. Thompson, D. Fraser

Ontogeny Collection

Piglets from 51 litters were weighed weekly over a 5-wk lactation in an experiment that studied the effects of farrowing crate design and other factors on variation in piglet weight. Of two farrowing crates used, one had low horizontal bars that tended to impede access to the upper row of teats, while the other had angled vertical bars which permitted freer access. Fourteen-day weights were more uniform in the vertical-bar crates than in the horizontal-bar crates (P < 0.025), but the difference waned by day 35 (P > 0.05). There were no significant differences in mean body weight owing to crate type (P < 0.05) for any of the weekly measurements but, by day 14, there was a significant linear trend (P < 0.05) at decreasing main body weight with increasing litter size. The interaction between crate type and litter size was significant at the later ages (P < 0.01 at day 35) because the linear trend was more pronounced for horizontal-bar crates than for vertical. Litters differed greatly in the uniformity of their body weights. Much of the variation became established in the first and, to a lesser extent, the second week after birth. In those weeks, weight gains were highly variable and were not closely related to weight at the beginning of the week. Thereafter, the established differences tended to be perpetuated to 35 d, because weight gains were largely proportional to body weight. Within-litter competition appeared to influence weight gain considerably.

Variation In Piglet Weights: Relationship To Suckling Behavior, Parity Number And Farrowing Crate Design, David Fraser, B. K. Thompson

Ontogeny Collection

Suckling behavior and weight change of piglets were studied during the first 2 wk after birth. Thirty-six litters comprised a balanced comparison of parity number (first or second), litter size (8, 10 or 12), and two farrowing crate designs, one of which had a low horizontal bar that tended to impede the piglets' access to the udder. Piglets showed the expected preference for the anterior teats although the preference was more apparent in the second parity than in the first. Teat fidelity was most pronounced at the two ends of the udder; piglets occupying the middle positions did more fighting …

Factors Affecting Thyrotropin Secretion In Superfused Rat Anterior Pituitary Cells, Frederick Scott Bartlow

Dissertations and Theses

The use of static in vitro pituitary cultures has been indispensible for examining the regulation of anterior pituitary hormone secretion. While the static cultures have shown the effects of various chemical stimulators of hormone secretion, the dynamics of such secretion has not been assessed before in vitro. The in vitro superfusion method, which partially stimulates in vivo physiologic conditions, allows for the observation of the dynamics of pituitary hormone secretion.

Connquest, Sandra Cookson, D.W. Allinson, G.S. Speer, R.W. Taylor, R.P. Prince, J.W. Bartok, D.W. Protheroe, D.R. Miller

Storrs Agricultural Experiment Station

No abstract provided.

Karyology And Morphometrics Of Three Species Of Akodon (Mammalia: Muridae) From Northwestern Argentina, Rubén M. Barquez, Daniel F. Williams, Michael A. Mares, Hugh H. Genoways

University of Nebraska State Museum: Mammalogy Papers

Chromosomal and morphometric studies were conducted on a sample from an assemblage of Akodon spp. occurring in various patterns of sympatry from the provinces of Catamarca, Jujuy, Salta, and Tucumán, Argentina. Results showed three distinct morphometric groups based upon size. Size also varied with age, but there were no significant differences in measurements of males and females. The three morphometric groups have distinct karyotypes. Akodon caenosus Thomas is the smallest of the three, and has a karyotype of 2n = 34, FN = 40. A. boliviensis tucumanensis J. A. Allen is intermediate in size and has 2n = 40, FN …

More Lambs By Mating Weaners, R J. Suiter

Journal of the Department of Agriculture, Western Australia, Series 4

Farmers can increase sheep numbers by mating ewe weaners. Trials have shoen that this does not affect the later performance of these ewes.

Differentiation Of Fourth And Early Fifth Stages Of Parascaris Equorum (Goeze, 1782) Nematoda: Ascaridoidea, P. A. Pilitt, J. R. Lichtenfels, P. A. Madden

Harold W. Manter Laboratory of Parasitology: Faculty Publications

The morphology of Parascaris equorum of horses was studied; light and scanning electron microscopy were used. Late fourth-stage larvae have narrow, rectangular lips bearing few, large. triangular, irregularly spaced denticles and the lips are not markedly set off from the body. The cutick of the late fourth stage is completely transversely striated, with incomplete longitudinal ridges creating a brickwork pattern; longitudinal alae are present. Total body lengths of fourth-stage larvae range from 10 to 32 mm. A single molting fourth-stage male was found to be 33 mm long. Early fifthstage nematodes have wide, trilobate lips with a deep transverse groove …

The Effect Of Selenium On The Toxicity Of Methyl Mercury In Medaka Embryos, Peter H. Krauth

All-Inclusive List of Electronic Theses and Dissertations

The purpose of this research was to investigate the effect of selenium upon methyl mercury poisoning in Medaka fish (Oryzias latipes) embryos. Selenium has been shown to provide a protective mechanism against mercury poisoning in some adult animals. Three experiments were done. In the first, selenium and methyl mercury were put directly in the growing medium of the eggs. In the second experiment, selenium was included in the diet of the parent fish. In the third part, methyl mercury exposure was delayed three days. The results of the first experiment were quite dramatic and showed a significant difference when selenium …

A Histochemical Study Of Tooth Development In The Chinese Hamster (Cricetulus Griseus), Robert B. Daszkiewicz

Masters Theses

The normal morphological development of the Chinese hamster (Cricetulus griseus) during the last week of gestation was studied. A review of the literature reveals no distinct study of tooth development in this species. An identical gestation period is found in the mouse (Mus musculus) making direct comparison between the embryos of the same age of the two species feasible. During this investigation, it was found that morphological tooth development in the Chinese hamster lagged behind that of the mouse by about 2 days. On day 14 of gestation in the Chinese hamster, the oral epithelium is …

High Pre-Mating Liveweights Improve The Lambing Performance Of Merino Ewes, R J. Suiter

Journal of the Department of Agriculture, Western Australia, Series 4

Analysis of lambing trials with Merino ewes has shown a highly significant association between pre-mating liveweight and lambing performance.

With May-June lambing ewes there was a 2.9 per cent, lambing increase for every extra 10 lb. liveweight; for July-August- September lambing ewes there was a 6.9 per cent, increase for every 10 lb. liveweight increase.

With the May-June lambing there was a critical weight below which twinning was negligible.

Later Mating Improves Lambing Results, R J. Suiter

Journal of the Department of Agriculture, Western Australia, Series 4

Ovulation studies in Western Australia have indicated that increased lambing percentages in crossbred and Merino ewes could be expected from mating in February-April rather than December- January.

Such increases have been demonstrated in time of lambing trials with crossbred ewes, but had not been seen in Merino flocks until recently.

This report summarises the results of time of lambing trials with Merinos carried out at the Merredin and Wongan Hills Research Stations between 1963 and 1969.

Forelimb Regeneration Study In The Adult Small-Mouthed Salamander (Ambystoma Texanum), John Farrell Williams

Masters Theses

No abstract provided.

A Histological Study Of The Postnatal Development Of The Bovine Testis, R. G. Fossland, A. B. Schultze

Nebraska Agricultural Experiment Station: Historical Research Bulletins

A limited number of detailed studies on the development of the bovine testis from birth to sexual maturity have been reported. Further study of bovine testis development appears desirable to furnish additional observations and to note variations that may occur during the developmental process. Information on the process of spermatogenesis should furnish a basis for experimental work designed to promote increased spermatogenic activity in the postpubertal testis as well as for work directed toward promoting complete spermatogenesis at an earlier than usual age. This report is a study of the histological picture of the testes from 56 bulls varying from …

White Muscle Disease Of Sheep : Symptoms And Pathology, M R. Gardiner

Journal of the Department of Agriculture, Western Australia, Series 4

WHITE Muscle Disease (WMD) was recognised for the first time in Western Australian sheep during the winter of 1960.

The first outbreak occurred on a property in the South Stirling district in the middle of July and this was followed by outbreaks in August, September and early October, at Mayanup, Kendenup, Mt. Barker, Duranillin, Kojonup, South Stirling and Pinjarra.

Incubation, R V. Vagg

Journal of the Department of Agriculture, Western Australia, Series 4

TH E artificial incubation of eggs is not a recent innovation. For many centuries, some species of birds—our mallee-hen being a typical example—have hatched out their eggs by the heat generated in mounds of decaying vegetation.Furthermore, they have shown considerable skill in maintaining the mounds at uniform temperatures throughout the hatching period.

A number of reptiles employ similar methods to hatch their eggs, although in these instances there does not seem to be the same need for carefully-controlled temperatures

Vitamins And Their Relationship To Animal Health, J Shilkin

Journal of the Department of Agriculture, Western Australia, Series 4

NUTRITIONAL problems are assuming more and more importance in stock as the years progress and while much stress is sometimes placed on the role of vitamins in nutrition, one should not lose sight of the fact that they are only part of a balanced ration which should include other constituents, such as proteins, carbohydrates and fats in suitable proportions.

Studies Of Prenatal Development In Farm Animals, L. M. Winters

Journal of the Minnesota Academy of Science

The central objective of these studies has been to gather as accurate data as possible regarding normal prenatal development in farm animals. Once this is established as a base we or other workers will be in a position to study the specific effects of unfavorable environments, such as deficiency rations, excess fat, etc. Our work has progressed far enough so that we are now incorporating some of the latter in our studies.

The Effect Of Potassium-Iodide On The Embryological Development Of The Chick With Special Reference To The Growth Of The Long Bones., David M. Polot 1904-1978

Electronic Theses and Dissertations

No abstract provided.

Spermatogenesis Of The Butterfly, Papilio Rutulus, John P. Munson

All Faculty Scholarship for the College of the Sciences

For a number of years I have been studying the spermatogenesis of Papilio rutulus (pl. 12, fig. 1) not ,with any one single problem especially in view, but with the aim of ascertaining the entire life history of its sperm cell, its various phases of development, its mode of growth and differentiation, the history of its several parts, and its relation to the organism.