^ ■ \ -■ , DESCRiPTION OF THE SIVATHERIUM, 



apex. They are long slips of bone, with nearly parallel edges, running 

 between the upper borders of the maxillaries, and joined to the ascending 

 process of the incisive bone, near their extremity, or connected only with 

 the maxillaries ; but in neither case projecting so as to form any consider- 

 able re-entering angle, or sinus, with these bones. 



In our fossil, the form and connections of the nasal bones, are very 

 different. Instead of running forward in the same plane with the brow, 

 they rise from it at a rounded angle of about 130°, an amount of saliency 

 without example among ruminants, and exceeding what holds in the Rhi- 

 noceros, Tapir, and Palseotherium, the only herbivorous animals with this 

 sort of structure. Instead of being in nearly parallel slips, they are broad, 

 and well arched at their base, and converge rapidly to a sharp tip which is 

 hooked downwards over-arching the external nostrils. Along a consider- 

 able portion of their length they are unconnected with the adjoining bones, 

 their lower margins being free and so wide apart from the maxillaries, as 

 to leave a gap or sinus of considerable length and depth in the bony 

 parietes of the nostrils. The exact extent to which they are free, is un- 

 luckily not shown iri the fossil, as the anterior margin of the maxillaries is 

 mutilated on both sides, and the connection with the incisives destroyed. 

 But as the nasal bones shoot forward beyond the mutilated edge of the 

 maxillaries, this circumstance, together with their well defined outline and 

 symmetry on both sides of the fossil, and their rapid convergence to a point 

 with some convexity, leaves not a doubt that they were free to a great 

 extent and unconnected with the incisives. 



Now to determine the conditions in the fleshy parts, which the struc- 

 ture in the bony parietes of the nostrils entails. 



The analogies are to be sought for in the ruminantia and pachydermata. 



The remarkable saliency of the bones of the nose in the Sivatherium, 

 has no parallel, in known ruminants, to guide us ; and the connection of the 

 nasals with the incisives, or the reverse, does not imply any important 

 difference in structure in the family. In the Bovine section, the Ox and 



