46 Description of the Sivatherium, [Jan, 



Regarding the first point, we have nothing sufficient to guide us with 

 certainty to a conclusion, as there are ruminants both with and without 

 incisives and canines in the upper jaw; and the Sivatherium differs most 

 materially in structure from both sections. But there are two conditions 

 of analogy which render it probable that there were no incisives. 1. In all 

 ruminants which have the molars in a contiguous and normal sei'ies, and 

 which have horns on the brow, there are no incisive teeth. In the camel 

 and its congeners, where the anterior molars is unsymmetrical and separat- 

 ed from the rest of the series by an interval, incisives are present in the 

 upper jaw. The Sivatherium had horns, and its molars were in a conti- 

 guous series : it is therefore probable that it had no incisives. Regarding 

 the canines there is no clue to a conjecture, as there are species in the same 

 genus of ruminants both with and without them. 2. The extent and 

 connections of the incisive bones are points of great interest, from the kind 

 of developement which they imply in the soft parts appended to them. 



In most of the horned ruminantia, the incisives run up bv a narrow 

 apophysis along the anterior margins of the maxillary bones, and join on 

 to a portion of the sides of the nasals ; so that the bony basis of the exter- 

 nal nostrils is formed of but two pairs of bones, the nasals and the incisives. 

 In the camel, the apophyses of the incisives terminate upon the maxilla- 

 ries without reaching the nasals, and there are three pairs of bones to the 

 external nostrils, the nasals, mamillaries and incisives. But neither in 

 the horned ruminants, nor in the camel and its congeners, do the bones of 

 the nose i"ise out of the plane of the brow with any remarkable degree of 

 saliency, nor are their lower margins free to any great extent towards the 

 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- 

 nocei'os, tapir, and palaeotherium, 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 in 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 structure 

 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 

 the Buffalo have the nasals and incisives connected : whereas they are 



