1869. | DR. J. E. GRAY ON THE TORTOISES. ail | 
sternal callosities are scarcely developed, only showing a slight 
roughness on the surface. Head olive, with a black central streak 
from the snout to between the eyes, which divides behind into three 
diverging streaks on the crown and nape; a streak from the nose, 
through the eye, and continued on the temple, to the side of the 
neck. The alveolar surface of the upper and lower jaws very broad 
the whole length of the outer edges; the alveolar surface of the 
upper jaw is so large as to cover the greater part of the palate, much 
more so than in Trionya gangeticus; in the lower jaw it is very 
broad, as broad hehind as before, and slightly concave. The central 
palatine groove in front of the internal nostrils narrow, deep. The 
bones of the dorsal shield are distinctly marked and separate; the 
vertebral plates are very narfow, nearly twice as long as broad; the 
costal ones are linear, scarcely broader at the outer ends, the last one 
being the least and narrow at the outer end. The odd bone in front 
is quite separate from the granular buckler, covered with skin, and 
quite smooth. The lateral sternal callosities are scarcely developed, 
only showing a slight roughness on the surface. The hinder pair of 
sternal bones are broad at the inner end and united together in front 
of the inner edges by two broad lobes. 
Very like the figure in Cuvier’s ‘ Ossemens Fossiles,’ v. t. 23. f. 5. 
6. AspiLus. 
The odd bone in front of the dorsal shield in the younger speci- 
men is separate, and smooth on the upper surface, and it becomes 
pitted and united to the costal by a straight suture in the adult 
animal. 
8. PoTAMOCHELYS. 
The odd anterior bone of the dorsal disk in the young animal is 
pitted on the surface and separate, but in the older ones it is united 
to the dorsal disk by a straight suture. The skull resembles that 
of Cyclanosteus. 
12, Caxuinia. 
Head small, elongate ; face narrow, tapering ; eyes lateral, superior. 
The jaws weak ; the alveolar plates narrow at the hinder part, trian- 
gular and broader in front. The lower jaw slender, narrower at the 
hinder part of the sides. The central palatal groove in front of the 
internal nostrils rather wide and deep. The dorsal disk oblong, 
broad. The odd bone in front of the dorsal shield separate, trans- 
verse, and pitted in the young animal; in the older one it is united 
to the front costal bones by a straight edge with two round perfo- 
rations, one on each side of the central part. The vertebral callo- 
sities narrow. The costal callosities scarcely broader at the outer 
edge, except the fifth and sixth pairs; the hinder pair short, and 
narrow at the outer ends. Sternal callosities four ; the lateral pair 
broad on the inner side ; the hinder or anal pair oblong triangular, 
oblique, with a straight inner edge. 
Aspidonectes, sp., Agassiz, not Wagler. 
