CHELONIA. 743 



palatal ridge, while in the lower jaw there is a broad concave surface behind 

 its ridge, only differing from the posterior groove of B. haska in its posterior wall 

 being less defined, and the sides of the longitudinal groove less developed. In B. 

 haska this central groove is prolonged to the symphysis, owing to the ridge of 

 either side meeting at that point ; but in B. Uneata the two ridges join behind 

 the symphysis, to wliich they are connected by a sharp central ridge, but this is 

 only a modification of the type of structure which is common to both skulls, 

 and which would hardly seem to merit the importance Dr. Gray has attached to 

 it. Moreover, in B. duvaucelli (not the skull figm^ed by Dr. Gray under that 

 name, which appears to be B. Uneata), there is a still further modification of 

 the mandible, while the palatal surface is nearly the same as m B. Uneata. In 

 B. duvaiwelU there is no groove behind the ridge, which is broad and flat without 

 any trace of a longitudinal groove, but the ridges, meeting as in jS. Uneata, are 

 prolonged by a central ridge on to the symphysis. "We have thus in B. Uneata, 

 a form intermediate in these skull characters between B. haska on the one hand, 

 in which they have their highest expression, and B. duvaucelli on the other, in 

 which they are least marked. Were it not that B. haska is so closely related in its 

 internal anatomy and the structure of its skull to B. Uneata and B. duvaucelli, 

 more importance might be attached to the absence of a fifth claw on its fore foot, but 

 this is little more than a dermic character, and not at all comparable to the absence 

 of a digit, wliich, when it does occur, is generally considered as of generic 

 importance. 



The skull is closely allied to the skull of B. Uneata, being much broader and 

 flatter in the frontal region and between the orbits than in B, haska, but less so than 

 in B. Uneata, with a much shorter and broader snout, with the pre-frontals only 

 slightly upturned. It is distinguished from the skull of B. Uneata by the much 

 greater breadth of the pterygoid region of the skull. The vomer also is much nearer 

 the anterior end of the basisphenoid than in B. Uneata. The internal nares are 

 oblong in B. Uneata, with the palatine margin slightly, if anything, inwardly convex, 

 whereas in B. duvaucelli these margins are outwardly convex, which gives an oval 

 contour to the conjoint openings. The palate also wants the third ridge which is 

 only indicated in B. Uneata, and the longitudinal broad eminence that occurs 

 between the traces of the third ridge. But the most distinguishing feature is the 

 total absence of the broad concavity and the longitudinal furrow that occur in 

 B. Uneata, posterior to the first alveolar ridge of the mandible. In B. duvaucelli, the 

 first alveolar ridge is broad and flat on its summit, without any furrow behind it. 



The stomach of a female measuring 8"* 2 5 in the length of its carapace has an 

 extent of 5'25 inches along the lower curve. The small intestine, which is of about 

 one-fourth the capacity of the large intestine, measures 35' 75 inches in length. The 

 latter begins by a sudden enlargement which projects more on one side than the other. 

 It has a length of 17 '50 inches. 



The dorsal division of the left lobe of the liver does not overlap the stomach, 

 but is wholly enclosed in the bend, and the ventral division only partially overlaps 



