Other Animal Sciences Commons^™

Response Properties Of Tibial Campaniform Sensilla On The Cockroach Leg In Restrained Preparations And Freely Moving Animals, Angela L. Ridgel

Theses, Dissertations and Capstones

The ability to detect changes in forces is important for effective use of a leg in posture and locomotion. This thesis examines how forces are detected in the legs of cockroaches by tibial campaniform sensilla. Campaniform sensilla are mechanoreceptors that encode forces through ovoid cuticular caps embedded in the exoskeleton. The tibial sensilla are unique in that they consist of two subgroups with mutually perpendicular cap orientations.

We characterized the responses of the tibial receptors in restrained preparations by applying forces to the leg at controlled magnitudes and rates. The tibial sensilla, as a group, were sensitive to increasing and …

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

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, …