yo 5. W. WILLISTON 



most cotylosaurs. Its delicate and slender teeth could have been 

 of no use in the capture of large prey; perhaps it preyed upon the 

 numerous small amphibians and reptiles that swarmed in such 

 regions. And doubtless it was more or less at home in the water, 

 though not strictly an aquatic animal. From Texas, however, 

 a very closely allied genus — Theropleura — is known to have more 

 flattened and cutting teeth, suggesting more active carnivorous 

 habits. 



Finally, the last and most divergent group of all the known 

 paleozoic reptiles of America is represented by a little, very slender, 

 and slender-legged reptile of about one foot and a half in length, 

 which I have called Araeoscelis. A description of this animal, 

 giving nearly every detail in its structure, is now in preparation 

 by the writer. Sufhce it to say here that Araeoscelis is not only 

 wonderfully lizard-like in form, but actually lizard-like in its 

 structure, or as nearly lizard-like as one could expect in such ancient 

 creatures; so lizard-like indeed that I firmly believe that it was 

 actually closely akin to the ancestors of all our lizards and snakes, 

 without a single character that would not be expected in the most 

 primitive lizard. Araeoscelis was an exceedingly fleet, climbing 

 and running reptile of the uplands, of purely terrestrial habits. 



In conclusion I may add that, whatever may be the merits of 

 these restorations as works of art, they have been drawn with most 

 scrupulous accuracy so far as form and proportions are concerned, 

 the musculature derived from the study of living reptiles. And, 

 as I have said, they are all based upon practically complete skele- 

 tons; in a few only the precise length of the tail is yet unknown, 

 or the front toes in Tremaiops and Cacops. 



