Page:Natural History, Reptiles.djvu/17

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TORTOISES.
9

as in other vertebrate animals, are all within, as are also the bones of the pelvis, and even the muscles of the thighs; so that a Tortoise has been described as an animal turned inside out. The

SKELETON OF TORTOISE.

jaws are destitute of teeth, but are invested with horn like those of birds, and form in fact a powerful beak. The head, neck, tail, and limbs, are clothed with a tough skin, in which are imbedded plates, either connected or detached.

The sphere of action of the Testudinata is either the land or the water. Of those which are aquatic, some inhabit marshes, pools, and rivers; others are exclusively marine. The walk of the terrestrial species is slow, even to a proverb; the legs are short, restricted in motion, and being placed at a distance from the centre, they form a sort of short crutches, able to drag the unwieldy