ii DESCRIPTION OF THE SIVATHERIUM, 



the horse has the upper lip endowed with considerable mobility ; and the 

 lower end of the nasals is at the same time free to a small extent. In all 

 the other genera, there is nothing resembling a prehensile organ in the 

 upper lip. 



In the Sivatheriiim, the same kind of structure holds, as is found in 

 the Pachydermata with trunks. Of these it most nearly resembles the Tapir. 

 It differs chiefly in the bones of the nose being larger and more salient 

 from the ChafFron ; and in there being less width and depth to the naso- 

 maxillary sinus, than the Tapir exhibits. But as the essential points of 

 structure are alike in both, there is no doubt that the Sivatherium was 

 invested with a trunk like the Tapir. 



This conclusion is further borne out by other analogies although more 

 indirect than that afforded by the nasal bones. 



1st. — The large size of the infra-orbitary foramen. In the fossil the 

 exact dimensions are indistinct, from the margin having been injured in the 

 chisseling off of the matrix of stone : the vertical diameter we make out to 

 be 1 .2 inch, which perhaps may be somewhat greater than the truth : but 

 any thing approaching this size, would indicate a large nerve for trans- 

 mission and a highly developed condition of the upper lip. 



2d. — The external plate of the bones of the cranium is widely separated 

 from the inner, by an expansion of tlie diploe into vertical plates, forming 

 large cells, as in the cranium of the Elephant : and the occipital is expanded 

 laterally into alse, with a considerable hollow between, as in the Elephant. 

 Both these conditions are modifications of structure, adapted for supplying 

 an extensive surface for muscular attachment, and imply a thick fleshy 

 neck, with limited range of motion ; and, in more remote sequence, go to 

 prove the necessity of a trunk. 



3d. — The very large size of the occipital condyles, which are greater 

 both in proportion and in actual measurement than those of the Elephant, 

 the interval between their outer angles, taken across the occipital foramen, 

 being 7.4 inches. The atlas, and the rest of the series of cervical vertebrae, 



