Date of Award

4-1936

Degree Type

Bachelors Essay

Degree Name

Bachelor of Science (BS)

Department

Biological Sciences

First Advisor

Paul L. Carroll

Second Advisor

William J. Grace

Abstract

The phylum Mollusca manifests the following characteristics: bilateral symmetry; three primary germ layers; free-living and sessile; marine and fresh-water; a shell modified to form either a bivalve or a univalve which gives an appearance of segmentation due to rings of growth or arrangement of certain parts of the shell as is seen in the class Amphineura, this is only apparent metamerism because the Mollusca are considered to be unsegmented animals; a coelom poorly developed; a foot; a mantle cavity; well developed digestive, circulatory, excretory, and reproductive systems. When one inspects a Chiton, an oyster, a snail, an octopus, or a squid, the characteristics listed above do not seem to have universal application. In some cases the shell may be infiltrated with calcium carbonate or be composed of only a chitinous substance; the foot may be modified for creeping, for grasping with tentacles or for sense-perception or may be rudimentary or entirely absent; the mantles may form an open or a closed cavity; the gills may form lamellae or filaments or may even be replaced by a primitive type of lung.

Comments

A Thesis Submitted to the Faculty of the College of Liberal Arts of Marquette University in Partial Fulfillment of the Requirements for the Degree of Bachelor of Science Milwaukee, Wisconsin.

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