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Articles 61 - 64 of 64

Full-Text Articles in Cell and Developmental Biology

Genetic Analysis Of Rhinichthys Atratulus (Pisces: Cyprinidae) In North Central West Virginia, Alan Harper Tennant Jan 1996

Genetic Analysis Of Rhinichthys Atratulus (Pisces: Cyprinidae) In North Central West Virginia, Alan Harper Tennant

Theses, Dissertations and Capstones

The blacknose dace, Rhinichthys atratulus, is a cyprinid minnow common to shallow streams throughout North America. It has been shown to be sensitive to anthropogenic stress and a study of the genetic nature of R. atratulus populations may yield information about their habitats. In West Virginia, two subspecies of R. atratulus are present, R. a. atratulus and R. a. obtusus, which are separated by the Allegheny divide. In north central West Virginia, R. a. atratulus was observed in the Cheat River drainage, an area previously thought be within the range of R. a. obtusus. Fish of the R. a. atratulus …


Postnatal Development Of The Neural Retina In A South American Opossum: Monodelphis Domestica, Tracy L. Soltesz Jan 1996

Postnatal Development Of The Neural Retina In A South American Opossum: Monodelphis Domestica, Tracy L. Soltesz

Theses, Dissertations and Capstones

Postnatal retinal development was studied in a marsupial opossum, Monodelphis domestica using light microscopy and 3H-thymidine autoradiography. For the light microscopic study, opossum neonates at 1, 3, 7, 14, 21, 25 and 28 days of age were euthanized, fixed and processed into paraffin sections for hematoxylin and eosin staining. The distinct ganglion cell layer, first observed on postnatal day (P) 7, was separated from the outer neuroblasts by the inner plexiform layer. The neuroblast layer was divided into inner and outer nuclear layers on P25 by the presumptive outer plexiform layer, indicated by discrete intercellular spaces located between the nuclear …


Geographic And Nongeographic Variation In The Genus Microtus (Mammalia: Rodentia) In West Virginia, Tina M. Savage Jan 1995

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, …


Variation In Leaf Anatomy In Ten Selected Species Of Carex (Cyperaceae) Representing Three Subgeneric Sections (Bracteosae, Multiflorae, And Squarrosae), Marion Rae Mallory Jan 1979

Variation In Leaf Anatomy In Ten Selected Species Of Carex (Cyperaceae) Representing Three Subgeneric Sections (Bracteosae, Multiflorae, And Squarrosae), Marion Rae Mallory

Theses, Dissertations and Capstones

Leaves of Carex (Cyperaceae) representing three subgeneric sections were collected from wide spread localities and observed for anatomical variation. Among the quantitative characters evaluated were, epidermal cell height, width, and number per unit area, bulliform cell height and width, ai r cavity length, width, and number per unit area, and number of stomata per unit area. some descriptive anatomical characters were leaf and keel shape, air cavity shape, sclerenchyma pattern, vascular bundle location, presence or absence of a hypodermis, nature of the mesophyll, silica body shape and location, presence or absence of epidermal projections, stomatal pattern, and subsidiary cell shape.