60 dr. j. e. gray on the trionychidjE. [Jan. 7, 



gradually wider behind ; central groove wide, rather deep, as wide as 

 the front edge of the large internal nostrils. Lower jaw rather weak ; 

 alveolar surface with a sharp edge, shelving inwardly ; front part 

 widest, concave ; sides rather narrower, with a concave upper edge, 

 gradually becoming narrower behind to the condyle. Length of the 

 skull to condyle lg inch ; diameter f- inch. 



This specimen was named Gymnopus javanicus by Bibron, and was 

 described by me as Trionyx frenatus in the Cat. Sh. Rept. p. 67, 

 where I thought it was the same as a Tortoise I had received from 

 Mr. Wallace, from Singapore : but the examination of the skulls has 

 shown that the former is the young of the North-American Platy- 

 peltis ferox ; and the latter proves to be merely a specimen of Dogania 

 subplana approaching maturity, which I had named Sarbieriafrenata, 

 an Asiatic species— showing the necessity of examining the jaws 

 and skulls of these animals. 



9. Callinia. 



Callinia, Gray, P. Z. S. 1869, p. 221 ; Suppl. Cat. Sh. Rept. 

 p. 108. 



Head elongate, rather thin, produced in front ; nose-hole large, 

 nasal bones projecting into its upper surface, acute ; orbits large ; 

 palate with a wide shallow central depression, as wide as the large 

 internal nostrils, and continued along its sides. Lower jaw weak, 

 thin ; alveolar margin concave, much wider in front, narrower on the 

 sides, especially behind. 



* The skull rather rounded in front ; nose-hole as broad as long ; 

 lower jaw rounded in front. 



1. Callinia spinifera. (Fig. 10, p. 61.) 



Trionyx spiniferus, Lesueur, Mem. Mus. xv. p. 258, t. 15. 



Aspidonectes spinifera, Agassiz, Contrib. p. 403, t. 6. figs. 1 & 2. 



Gymnopus spiniferus (part), Dum. et Bibr. Erpet. Gen. ii. p. 477, 

 t. 22. fig. 1. 



Callinia spinifera, Gray, P. Z. S. 1869, p. 220 ; Suppl. Cat. Sh. 

 Rept. p. 109. 



Trionyx ferox (part), Gray, Cat. Sh. Rept. p. 63. 



Trionyx ferox, e, Holbrook, Herpet. N. Amer. ii.t. 1. 



Trionyx argus, Gray, Cat. Sh. Rept. p. 68. 



Tyrse argus, Gray, Knowlesley Menag. t. 



Young. — Back with dark rings. 



Trionyx ocellatus, Lesueur; Wied, Voy. Amer. Sept. hi. p. 244. 



Trionyx annulatus, Wied, Voy. Am6r. Sept. iii. p. 242. 



Hab. North America. 



Skull elongate, producedin front, roundedat the end; nose-hole large, 

 as broad as long, with the nasal bones projecting into the upper surface, 

 acute ; orbits very large ; palate with a wide, rather shallow, central de- 

 pression, as wide as the front of the large nostrils, and continued round 

 the sides of the nostrils, and rather wider than they behind. Lower 

 jaw rather weak, regularly tapering in front, where it is rounded; 



