136 



THE PERMO-CARBONIFEROUS RED BEDS OF 



concealed in the water, with only the nose and eyes exposed, as deeply as any 

 Eryops. It is possible that the great incisors were used, as has been suggested 

 for LaUdosaurus, to excavate burrowing animals or detach clinging molluscs. 

 If this were true the animal would not have ranked with Eryops as a preda- 

 ceous form. Its main defense was its ability to take to the water freely, if 



Fig. 20. — Restoration of Limnoscelis paludis Williston. About one-tenth natural size. 



attacked upon the land, or in its rapidity of motion if attacked in the water. 

 The great incisor teeth would have been no mean weapons if the creature 

 was driven to the use of them. 



Bolosaurus. — This was a small form, not over 30 to 40 centimeters in 

 length. From the imperfect skulls and associated limb bones and vertebrae, 

 it appears to have been a cotylosaurian, with a rather slender body, a long 

 tail, and rather moderately long ribs. The teeth resemble those of Diadectes 

 closely enough to suggest that it fed upon insects and small crustaceans and 

 molluscs with weak shells. As noted above. Broom has suggested that Bolo- 

 saurus is not related to Diadectes. 



Pariotichus, Isodectes, Ectocynodon. — These, with probably many other 

 related forms as yet undiscovered, were small lizard-like creatures which 

 lived in the thick vegetation, or hid among the rocks to escape the larger 

 carnivorous forms. 



Captorhinus (fig. 21). — This genus was very rich in individuals in Clear 

 Fork time. It reached a foot or more in length, including the not very long 

 tail. The head was large in proportion to the body, the limbs well formed 

 and terminating in strong feet with fairly long digits. It was active, and 



Fig. 2 1 . — Restoration of Captorhinus sp. About one-third natural size. 



probably able to move with considerable rapidity for a short distance. The 

 position of the orbits and nares and the well-developed articulations of the 

 limb bones show that they were terrestrial in habit. Either upon the shores 

 or in the damp places of the land, they sought the small invertebrates, includ- 

 ing hard-shelled forms, upon which they fed. 



