Thesis (Ph. D.)--University of Queensland, 2001. / Includes bibliographical references.

Deep continuous layers of iridophores were discovered in certain Asian Agkistrodon species. A survey of available snakes showed the banded iridophores to be present in North American Crotalus and Sistrurus also, indicating an unreported morphology to be a possible common phenomenon. Skin samples from 147 species and/or subspecies of snakes of the families Leptotyphlopidae, Boidae, Colubridae, Elapidae and Viperidae were examined and photographed by polarized light microscopy. Dermal iridophore patterns were visually identified and categorized as (1) isolated cells, (2) lightly layered, (3) moderately layered and (4) heavily layered. Selected specimens were examined and photographed by electron microscopy; isolated iridophore ultrastructure and layered iridophore ultrastructure patterns are illustrated and described. Reflectometry of four selected crotalids reveals positive correlation between iridophore quantities and albedo, but habitat adaptation and correlation of individual species/subspecies is difficult to show and only subjectively suggested. Published phylogenies of the species of the genera Agkistrodon, Calloselasma, Deinagkistrodon and Hypnale are revised to reflect taxonomic works and are correlated with iridophore pattern data. Phylogenetic relationships of Crotalus and Sistrurus are also revised with recent publications; they are neither supported nor contradicted because layered iridophores occur in all of their phylogenetic groups.

No description available.

This thesis has presented experimental evidence for the therapeutic use of semantic desensitization in the modification of a snake phobia. An experiment was conducted utilizing 66 introductory psychology and experimental psychology students, who responded in a strongly negative fashion to the word “snake” as it appeared on a semantic differential scale. S’s were randomly assigned to either an experimental group or one of two control groups, where different procedures were used to test the effectiveness of this technique. A significant reduction in the meaning attended to the word “snake” was found after counterconditioning procedures were used for the experimental group. A slight reduction was found in control group I, as was hypothesized and no reduction was found for control group II. It is concluded that counterconditioning utilizing semantic desensitization is an effective and efficient technique in altering meaning attended to a phobic object.

Thesis (Ph.D.) -- University of Adelaide, Dept. of Paediatrics, 2000. / Includes bibliographical references.

Thesis (Ph. D.)--University of Michigan, 1931. / Caption title. Thesis note on label mounted on cover. "Abdruck aus Zoologische jahrbücher ... Band 52, Heft 2." "Literaturverzeichnis": p. 213-215.

Thesis - Univ. of Michigan. / "Contribution from the Department of Zoölogy, University of Michigan." "Reprinted for private circulation from Physiological zoölogy, vol. XV, no. 2, April, 1942."

Thesis (Ph. D.)--University of Michigan, 1931. / Caption title. Thesis note on label mounted on cover. "Abdruck aus Zoologische jahrbücher ... Band 52, Heft 2." "Literaturverzeichnis": p. 213-215.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1936. / Typescript. Includes abstract and vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 15-16).

No description available.