176 



FOSSIL TURTLES OF NORTH W1IRICA. 



the interorbital space, whereas in T . elkader the same suture is equal to the whole width of the 

 interorbital space. 



T. brachyrhina is a species with a blunter snout, a narrower lower jaw, and a much shorter 

 symphysis. The skull is narrower behind in proportion to the length. 



T. procax also has a relatively narrower skull and the choanal are placed further behind 

 the snout. 



T. bauri, having been founded solely on portions of the shell, can not be compared with 

 any species based on the skull alone. 



Toxochelys procax Hay. 



Figs. 224-22S. 



Toxochelys procax, Hay, Bull. Amer. Mus. Nat. Hist., xxi, 1905, p. 181, figs. 13, 14. 



The type of the present species is a large, but somewhat damaged, skull which belongs to 

 the American Museum of Natural History, New York. Its number is 234. It was obtained 

 from Mr. H. T. Martin, who collected it in the Niobrara deposits along the Smoky Hill River, 

 in Kansas, in 1901. On the lower surface, the lateral wings of the pterygoids are broken away; 

 also the hinder extremity of one maxilla, and a small portion of the palatines. On the upper 

 surface, the greater part of the frontals and panetals is gone, as well as the whole ot the jugals, 



Figs. 224-228. Toxochelys procax. Skull and lower jaw. 



224. Upper aspect of anterior portion of skull of type. 



225. Skull of type, showing palatal surface. 



226. Tip of lower jaw, with section (226a) along 



svmphvsis. No. 234 A. M. X. H. 



227. Tip of lower jaw. No. 220 A. M. N. H. 

 22S. Dentarv hones. No. 2050 Kansas Univ. 



quadratojugals, and squamosals. On the lower jaw there are present a portion on each side 

 ot the symphysis and the hinder end of one dentarv. 



The form of the skull ( bos. 224, 225) is like that of T . latiremis, except that the outlines of 

 the maxillae, as seen from below, are nearly straight, until the snout is approacht; whereas 

 in T. latiremis the whole outline is convex. The skull is likewise more elongated than that of 

 T. latiremis. The interorbital space is 27 mm. wide; and the pterygoids, where narrowest, are 



