160 Fossil Gavial from New Jersey. 



colour, very minutely striated, and, in a proper light, appears 

 divided into a number of minute facets. We cannot, however, 

 from this small fragment, aver that the same appearance per- 

 vades the whole crown of the tooth ; nor can we pronounce 

 with certainty that the teeth were furnished with edges. 



PL III. Jig. 9, or light Dental Bone. 



This fragment, iu fact, consists of portions of three bones ; 

 but in the figure, the right dental bone only is shown, in order 

 to exhibit the figure and direction of the sockets. Its principal 

 dimensions are as follow : — 



Total length 5'7. 



Breadth undetermined, on account of the imperfection of 

 the fragment. 



Depth at symphysis 2*1. 



Depth, just anterior to the second tooth, 1*7. 



Depth of socket behind, 1"6. 



Depth of jaw at anterior portion 1*6. 



Distance between 1st and second alveole -9. 

 between 2d and 3d '7. 

 between 3d and 4th '4. 



Of the fourth, or posterior socket, only a portion remains. — 

 The third is filled up with the body of a tooth, which is visible 

 in its whole length, and exhibits its base compressed in the 

 direction of the vertical plane of the jaw. The second and first 

 alveoles are likewise filled with the body of teeth, but are con- 

 cealed in consequence of the perfect state of the bone in these 

 places. At the anterior part of this bone is a portion of ano- 

 ther socket, which cannot be exhibited in the figure. Con- 

 nected with the dental bone are two others, which will be better 

 understood when we connect these fragments in their original 

 position. Vt^e shall then have fig. 10, — a large and important 

 portion of the lower jaw of a fossil reptile. 



In this figure a represents the fragments of the left, and b of 

 the right dental bones already described, as seen from above. 



