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Page:Popular Science Monthly Volume 73.djvu/571

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567
A GREAT PERMIAN DELTA
PSM V73 D571 Skull and a restored diplocaulus.png
Fig. 12. Skull of Diplocaulus, showing the upper and lower surfaces. Fig. 13. Restoration of Diplocaulus.

in the coal beds of South Joggins in Nova Scotia; they wrapped themselves in armor and they hid themselves in the ground.

It is possible to describe but a very few of the forms that are known. Eryops was the largest of the amphibian tribe, with a length of about eight feet; it was not unlike a great overgrown newt or salamander with weak sprawling limbs that could not raise the body from the ground, except by a great effort. The skull had a length of two feet and a half in the largest specimens and the lower jaw was hinged at the posterior end of the skull, so that the animal had a most tremendous gape. The jaws were armed-with sharp conical teeth, which in the anterior portions of the jaws were developed into powerful tusks. Probably the animal played a somewhat similar part in the Permian waters to that of the modern alligator, lying nearly covered in the water with only the eyes and nostrils exposed, which were placed on the top of the skull for the purpose, and gliding slowly upon its prey until within a distance that made possible a sudden fierce rush which ended with the passage of the victim down the capacious maw of the Eryops.

Contrasted with Eryops, and probably frequently its victim, was the small Diplocaulus. Though still imperfectly known, enough has been made out about this animal to show that it possessed a form even more grotesque than that of the high-spined reptiles. The head, as shown in Fig. 12, was extremely flat and shaped like an exaggerated crescent with strong horns or spines projecting to the rear from the posterior corners. The eyes and nostrils were located far forward toward the anterior end and were directed straight upward. The lower jaw was