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Spermatogenesis And Histology Of The Testes Of The Caecilian, Chthonerpeton Indistinctum, Rafael O. De Sá, Nibia Berois

Biology Faculty Publications

Macroscopically, the testes of Chthonerpeton indistinctum consist of a series of oval lobes. The number and size of lobes is variable in Chthonerpeton indistinctum. Histologically, the testes are divided into structural units, locules separated by septa of connective tissue. Inside of each locule spermatogenesis takes place in cysts of germinal cells that divide synchronically. Chthonerpeton indistinctum is divided chronologically into four stages of development based on the shape of the nuclei of the spermatids and their arrangement in the cyst: (1) round, (2) kidney shaped, (3) attenuate, and (4) bouquet arrangement.

A Survey Of Cellular Slime Molds At Selected Sites On The James River, Virginia, Nathaniel Lemaster Armistead

Master's Theses

The flood plain of the James River in Virginia supports a variety of deciduous forest associations and has not been examined previously for dictyostelids. This thesis is primarily concerned with the results of a survey of dictyostelids at selected sites in the James River basin. Some incidental observations concerning possible ecological relationships between dictyostelids are included.

Seven of the plant communities of Virginia described by Harvill, Stevens and Ware (1984) afe present in the areas surveyed and collection sites were established accordingly: (1) Mountain Pine-Oak Heath, (2) Pine-Oak Heath, (3) Oak-Hickory Forest, (4) Alluvial Hardwood Forest, (5) Beech-Maple-Tuliptree Forest, (6) …

A Survey Of Cellular Slime Molds At Selected Sites On The James River, Virginia, Nathaniel Lemaster Armistead Iii

Master's Theses

Forty-three sample sites representing seven plant associations were surveyed for cellular slime molds in the James River basin from the head-waters to the mouth of the James River. Dictyostelium mucoroides, Q. minutum, Q. purpureum, D. discoideum, Polysphondylium violaceum and P. pallidum were found in all associations. Dictyostelium lacteum was found in all but the Maple-Basswood association. The remaining species were unique to the Alluvial Hardwood association and the following respective forest types: D. polycephalum to Oak-Hickory, D. giganteum to Oak-Hickory and Mixed Mesophytic, and D. rosarium to Mixed Mesophytic. A percentage similarity test indicated that, with regards to the observed …

Apid Increase In Serum Calcium In Response To Stress In Pomoxis Nigromaculatus, Black Crappie, Severn Borden Churn

Master's Theses

Serum calcium levels were determined colorimetrically in Pomoxis nigromaculatus, the black crappie, subjected to rapid changes in temperature. Two experiments were conducted; in the first, fish were exposed to stress for 30 minutes before measuring serum calcium, and in the second, fish were exposed to stress for 5 minutes and returned to normal conditions for 25 minutes before measuring serum calcium. Condit ion (K-value) and sexual development were noted for the fish. Serum calcium increased in all stressed fish, regardless of sex, but higher serum calcium values were observed in stressed mature females than in stressed males or stressed immature …

Genetic Engineering, W. John Hayden

Biology Faculty Publications

Why do so many biologists express so little concern for biology as a whole and such contempt for fields other than their own? The current debate on release of genetically engineered organisms into the environment, specifically, J. E. Fox's recent reply (Letters, 18 Oct., p. 237) to an earlier letter by R. K. Colwell et al. (12 July, p. 111), offers a case in point.