1836.] 



a new Fossil Genus of the Sivdlik range. 



225 



and thickj extending to the point of the muzzle, and of great strength 

 to support the horns of the animal : and the upper lip is broad, thickj 

 and very mobile, but little elongated. In the Elephant, they are very 

 short, and the incisives enormously developed for the insertion of the 

 tusks, and the trunk is of great length. In the Tapir, they are short 

 and free, except at the base, and projected high above the maxillaries j 

 and the structure is accompanied by a well developed trunk. In the 

 other Pachydermatous genera, there are but two pairs of bones to the 

 external nostrils, the nasals and the incisives : the latter running up 

 so as to join on with the former ; and the nasals, instead of being short 

 and salient, with a sinus laterally between them and the maxillaries* 

 are long, and run forward, united to the maxillaries, more or less 

 resembling the nearly parallel slips of the Ruminantia. Of this genera,; 

 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 ex-* 

 tent. In all the other genera, there is nothing resembling a prehen- 

 sile organ in the upper lip. 



In the Sivatherium, 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 their being less width and 

 depth to the nasomaxillary 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 chiseling 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 transmission, and a highly developed condition of the upper 

 lip. 



2a?. — The external plate of the bones of the cranium is widely sepa- 

 rated from the inner, by an expansion of the diploe in vertical plates, 

 forming large cells, as in the cranium of the Elephant : and the occi- 

 pital is expanded laterally into alse, with a considerable hollow be- 

 tween, 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 mo- 

 tion ; 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 Ele- 



