3. PODOCNEMIS. 201 
Mesoplastral bones small, lateral, wedged in between the hyo- 
and the hypoplastra; plastron large, without hinge, with strong 
axillary and inguinal buttresses. A bony temporal roof, the quad- 
ratojugal forming a suture with the parietal; alveolar surface of 
upper jaw with one or more ridges; a single shield between the 
eyes; a pair of large parietal shields and an interparietal. Digits 
broadly webbed, fore foot with five claws, hind foot with four. 
Tail very short. 
South America and Madagascar. 
Fig. 51. 
Shell of Podocnemis sextuberculata. 
Synopsis of the Species. 
I. Forehead concave ; jugal and quadrate bones separated. 
A. Alveolar ridges of upper jaw strong, running along the whole 
length of the jaw. 
Mental barbels two; a single inter- 
Paietalshielah poets cee cuss erse sere cop 1. dumeriliana, p. 202. 
Mental barbels two; two azygous shields 
between the parietals ............ 2. lewyana, p. 203. 
AGSIM@IOW DET DOM cs. mae wee a te Woe 3. unifilis, p. 203, 
