. Elements of biology; a practical text-book correlating botany, zoology, and human physiology. Biology. XXIV. REPTILES The Spotted or Mud Turtle (Chelopus guttatus). — For a classroom exercise use living turtles. The body is flattened, and is covered on the dorsal and ventral sides by a bony framework. This covering is composed of plates cemented to the true bone underneath, the whole forming one horny cover. What is the general arrangement of these plates ? The dorsal covering is known as the carapace, the ventral one the plastron, the connection between them the bridge. Allow the animal to
. Elements of biology; a practical text-book correlating botany, zoology, and human physiology. Biology. XXIV. REPTILES The Spotted or Mud Turtle (Chelopus guttatus). — For a classroom exercise use living turtles. The body is flattened, and is covered on the dorsal and ventral sides by a bony framework. This covering is composed of plates cemented to the true bone underneath, the whole forming one horny cover. What is the general arrangement of these plates ? The dorsal covering is known as the carapace, the ventral one the plastron, the connection between them the bridge. Allow the animal to remain quiet for a moment, then touch the head suddenly. What is one function of the shell? In the box turtle this adaptation is made more evident by a hinge in the plastron which fits over the head and legs after they are withdrawn into the shell. Adaptations. — Place a lively turtle on its back. How does it attempt to regain equilibrium ? Notice the long neck. The long neck and powerful horny jaws are of great use to the animal in food getting. Allow the turtle to crawl on the table. Then place it in a dish of water. How are the legs adapted to movement in the water ? How is the foot adapted for other purposes ? Turtles are very strong for their size. The stout legs carry the animal slowly on land, and in the water, being slightly webbed, they are of service in swimming. The strong claws are used for digging especially at egg-lay- ing season, for some forms of turtles dig large holes in sandy beaches in which the eggs are deposited. Watch a turtle feeding. Notice that the claws are used. How? The absence of teeth makes it necessary for the turtle to tear the food with the aid of the strong claws. The sense of hearing in the turtles is not keen. The tympanic membrane can be seen just behind the eyes on the sides of the head. Can you deter- mine by experiment anything regarding keenness of vision in the turtle ? Is the turtle protectively colored? Describe any evidences you
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