Date of Award

5-1940

Degree Type

Bachelors Essay

Degree Name

Bachelor of Science (BS)

Department

Biological Sciences

First Advisor

William N. Steil

Second Advisor

Donald J. Keegan

Abstract

The turtles have a bony investment or shell, into which the legs, head, and tail maybe drawn. In some turtles there is a hinge on the lower part of the shell that enables the animal to enclose itself more completely. Turtles which have no way of defending themselves other than by their shells have a well developed plastron and carapace for protection, but our vicious friend the snapping turtle whom nature has provided with powerful jaws and muscles has a comparatively small plastron. The marine turtles have the limbs fin-like, indicating their aquatic life. The land turtles have them short and blunt and provided with claws for better use in a completely terrestrial life. The pond turtles have them more or less between the two conditions, indicating amphibious habits. the head of the turtle has a marked reptilian character having a broad pointed head, the skin being covered with horny scales of various sizes, the jaws being incased in horny beaks with sharp cutting edges, while teeth are entirely absent. The eyes are well protected by the bony ridges of the skull as well as by thick opaque eyelids called nictitating membranes. Concentric lines are usually to be found around the epidermal plates of the carapace and plastron. They are the lines of growth and show the increasing size of the scales to accommodate the growth of the animal.

Comments

A Thesis submitted to the Faculty, of the Undergraduate School of Marquette University, in partial fulfillment of the Requirements for the Degree of Bachelor of Science, Milwaukee, Wisconsin

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