430 EXPLANATION OF THE PLATES. 



PLATE II. 



Fig. 1. Exact view of the tusks of a large animal discovered by Drs. 

 Mitchill and Townsend, at Chester, Orange county, state of 

 New-York, in May, 1817. They were denuded lying in this 

 horizontal position. The tusks were smooth, and of a yellow- 

 ish brown and mottled appearance. This elegant surface was 

 traceable all around and above the upper grinders, which were 

 seated, as here represented, in the tusks themselves. The 

 sharp edge of bone which seems to have surrounded the roof 

 of the mouth, and which is seen to terminate behind, in condy- 

 loid surfaces, for the reception of the cervical vertebrae, was 

 afterwards exposed. The space within this circle of bone was so 

 mutilated and crumbled, that an xact delineation could not be 

 taken. The two triangular flat plates of bone, observed at the 

 divergence of the tusks, were continuous into them, and not 

 divided by sutures. It will be seen, however, that they are 

 separated from each other their whole length, by a longitudi- 

 nal fissure, until they are lost in the convergence of the tusks. 

 The posture of the animal was supine, or on his back, and he 

 had lain in this manner, probably undisturbed, since his death. 

 The length of the left tusk, which was wholly exposed, is 9 feet 

 along the curve. It made a bold curvature outward and a little 

 upward. The right tusk was 7 feet along the curve, and had 

 a direction in a plane, diverging very little from a perpendicu- 

 lar. These bones lay about 6 feet below the surface. Diame- 

 ter of each tusk at the divergence, 8 2-3 inches. Greatest 

 breadth of the circular edge of bone, '25 inches. Distance 

 from the condyloid surfaces to the upper grinders, 18 inches. 



l*'ig. 2. Side view of the lower jaw with the two grinders in siture. 

 Length, from the condyle to the extreme point of the chin, 3G 

 inches. Length along the base, 80 inches. Length of the 

 front, or smaller grinder, 35-8 inches. Breadth, 2 7-8 inches. 

 Length of the larger, 61-2 inches. Greatest breadth, 3 1-2 

 inches. 



Fig. 5- This thin flat plate of bone lay about ten feet deeper, and im- 

 mediately under, and parallel to the circular edge of bone 

 already described. It is separated by a longitudinal suture, 

 and before its bifurcation is contracted in its breadth, and 

 bent down to form a sinus on each side, apparently for the 

 inception of temporal muscles* 



