NORTH AMERICA AND THEIR VERTEBRATE FAUNA. 



145 



cave top, and a pineal opening even larger, proportionally, than in Diadectes. 

 The large eyes were on the side of the head ; the nostrils on the lower side of 

 the blunt, projecting snout, and directed downward and forward. The body 

 was quite broad, with well-developed ribs on nearly all of the presacral verte- 

 brae. The limbs were strong, the anterior the longest, terminating in broad, 

 stout feet. The tail was long and very slender. The teeth upon the edges of 

 the jaws are few and blunt, leading Williston to the conclusion that it was 

 phytophagous and moved slowly over the flat river plains, "perhaps feeding 

 upon succulent meadow vegetation." Aside from the fact that a study of the 

 possible food-supply does not afford any evidence of a suitable vegetation, 

 the teeth seem to be fviUy as well adapted to a diet of soft or protected 

 invertebrates. 



The large eyes, enormous pineal foramen, and the well-developed sense 

 of smell indicated by the large nasal cavities, together with the evident help- 

 lessness and lack of speed, suggest that the animal was dependent for its 



Fig. 30. — Restoration of Casea broilii Williston. About one-tenth natural size. 



safety upon concealment, or nocturnal habits. Williston has also noted that 

 the broad, squat body is such as coinmonly occurs in desert reptiles, and sug- 

 gests that Casea may have lived in dry and heated localities. 



Areoscelid.^. 



AreosccUs (fig. 31). — In the descriptions attempted above most of the 

 animals have been found to be dwellers in the "lower jungle" or in the water. 

 A few appear to have been dwellers on the higher lands. But a single genus, 

 Areoscelis, has been recovered to show that there was a life of the "upper 

 jungle." The remains described by Williston are those of an animal possess- 

 ing extraordinarily light and slender bones. The skull and girdles are too 

 imperfectly known to discuss, but the bones of the limbs are very long^ 

 hollow, and light, without evidence of the attachment of powerful muscles. 

 In every way the skeleton suggests great speed and agility, equaling in this 

 respect any living lizard. The bones are those of a swift terrestrial, or, more 

 probably, arboreal creattire. The branches of the great lycopods, or of the 



