Thesis (Ph. D.)--Johns Hopkins University, 1916. / Vita. Half-title: Part II, Gastropods and discussion of results. "Reprinted from Carnegie institution of Washingtonn Publication number 385 ... 1928." "Literature list for Miocene mollusks from tropical America": p. 42-48.

Thesis (M.S.)--University of Wisconsin--Madison, 1961. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 60-66)

Inaug.-diss.--Halle-Wittenberg.

No description available.

Thesis (Ph. D.)--University of Chicago, Committee on Evolutionary Biology, December 1999. / Includes bibliographical references. Also available on the Internet.

Recent specimens of the genus Diodora from the Smithsonian Institution Mollusc Collection were examined for the neontological portion of this study. Species included were D. cayenensis, D. listeri, D. sayi, and D. tanneri. Fifty eight measurements were made on each specimen and recorded with latitude and water depth at each collection site. Fifty specimens were selected as reference specimens, photographed, their perimeters digitized, and ornamentation and foramen shape evaluated qualitatively. Principal Components Analysis shows that subtidal specimens are generally flatter, have a less constricted foramen and a greater number of ribs than intertidal specimens. Specimens from higher latitudes have a less constricted foramen and an increased number of ribs. In the subtidal sample, larger specimens characterize higher latitudes. Analysis performed on all specimens of D. cayenensis, reveals 1.) a decrease in mean shell size and relative shell height in individuals collected from below the intertidal zone, 2.) shells from the province north of Cape Hatteras, N.C. have significantly more ribs than those of the same species from further south, and 3.) Gulf specimens are taller and relatively heavier for their size than those found elsewhere. More than 500 fossil Diodorids from Smithsonian Institution collections were measured and analyzed as were the recent specimens. Shell morphology varies latitudinally like those of recent subtidal Diodorids: higher latitude specimens have more ribs and a less constricted foramen. Geologic age has little or no correlation to form. / M. S.

The subgenus Rexmela, located primarily in Florida, is newly evolved, dating back 1.6 million years, first occurring in the Ayer's Landing Member of the Caloosahatchee Formation. This subgenus has highly variably shell morphology and has led to the erection of several species and subspecies. In order to provide a quantitative methodology with which to differentiate between populations, samples of Recent and fossil populations were collected and measured for a variety of parameters. The parameters measured included length, width, spire height, and several angles, and allowed for a discriminate analysis to be completed. The analysis supported the distinction of several of the populations as ecophenotypes. Paleoenvironments of the fossil populations were then recreated using analogues of Recent populations. / by Crystal Pletka. / Thesis (M.S.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.