THE SKULLS OF ARAEOSCELIS AND CASEA 745 
Broom" has recently expressed his belief that Araeoscelis is 
closely allied to Bolosaurus, a genus hitherto placed among the 
Cotylosauria by Cope, Case, and Huene, the type of a distinct 
family, the Bolosauridae. He has described a new genus from 
among the material in the American Museum which had hitherto 
been confounded with Bolosaurus, but of whose distinction from 
Araeoscelis he was not sure. So far as his descriptions and figures 
go (aside from the restorations), there is nothing to distinguish 
Fic. 2.—Casea Broilii Williston. <A, skull from side; B, left mandible, both ? 
natural size; art, articular; ang, angular; c, coronoid; d, dentary; m, maxilla; po, 
postorbital; pm, premaxilla; sp, splenial. 
Ophiodeirus from Araeoscelis, save perhaps in the teeth, in which I 
think heisinerror. The teeth of Araeoscelis are simple throughout, 
without accessory cusps, and they are distinctly thecodont. There 
are, however, some differences in the teeth among the material 
which I have referred to Araeoscelis. Typically there are fourteen, 
or possibly fifteen, teeth in the maxilla, of the size I have shown in 
the figure. Another specimen, consisting of the maxilla and mand- 
ible only, has at least sixteen teeth in the maxilla, all of a uniform 
small size; yet another skull has fourteen teeth, all of nearly uni- 
form size. Bolosaurus comes from the Wichita beds, doubtless 
t Bull. Amer. Mus. Nat. Hist., XXXII, 509, October, 1913. 
