502 



FOSSIL TURTLES OF NORTH AMERICA. 



pits are larger. On the outer ends ot the costals the pits are mostly in rows and there are only 

 three or four in a line of the length given. 



All the parts of the plastron (fig. 657) are present. The limhs of the entoplastron are 1 12 

 mm. long. The epiplastra are 18 mm. broad anteriorly and about 100 mm. long. The hyohy- 

 poplastral suture is 143 mm. long. The bridge is 56 mm. wide. Each xiphiplastron is 1 10 

 mm. long and 75 mm. wide. The sculpture of the plastron is finer than that of the carapace. 



The skull (figs. 658-660) is complete and little distorted. It resembles closely that of 

 Platxpcltis ferox, but the profile descends more abruptly from the middle of the orbits. The 

 length from snout to occipital condyle is 102 mm. From the outside of one quadrate to that 

 of the other is 67 mm. The orbits are large, the diameter being 20 mm. The roof of the mouth 



\U&Ji 



662. 



- 661. 



Figs. 658-662. Aspideretes singularis. Parts of type. X3. 



658. Upper view of skull. 659. Lower view of skull. 



660. Right side of skull. 661. Fore leg. 662. Hind leg. 



is mostly concealed by the bones of the tongue. It is seen, however, that the choanae are placed 

 25 mm. behind the tip of the snout. The shoulder-girdle and bones of the foreleg (fig. 661) 

 differ little from those of the living species just mentioned. One forefoot is nearly complete. 

 The pelvis and hinder limbs (fig. 662) offer no peculiarities. The bones ot the hinderfeet 

 are not completely preserved. 



The sculpture of this species resembles that of A. sagatus and A. puercensis. From the 

 former it differs in having a larger portion of the nuchal bone devoid of sculpture and in having 

 this bone extend much farther across the outer end of the first costal. From A. puercensis it 

 differs in having the nuchal more closely joined to the first costals and a coarser sculpture 

 on the outer ends of the costals. There are differences in the plastra of the two species. 



