278 Dr. Falconer and Capt. Caiuley 



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 

 ruminan'ts which have the molars in a contiguous and normal series, and 

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

 and its congeners, where the anterior molars are unsymmetrical and sepa- 

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

 upper jaw. The Sivatherium had iiorns, 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 connexions of the incisive bones are points of great interest, from the 

 kind of development which they imply in the soft parts appended to 

 them. 



In most of the homed Biiminaniia, the incisives run up by 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 external 

 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 maxillaries 

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

 ternal nostrils, the nasals, maxillaries, and incisives. But neither in the 

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

 the nose rise 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 be- 

 tween 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 connexions of the nasal bones are very dif- 

 ferent. 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 with- 

 out example among ruminants, and exceeding what holds in the rhino- 

 ceros, 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 consi- 

 derable portion of their length they are unconnected with the adjoining 

 bones, their lower margins being free and so wide apart from the maxil- 

 laries 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 

 unluckily not shown in the fossil, as the anterior margin of the maxillaries 

 is mutilated on both sides, and the connexion with the incisives destroyed. 

 But as the nasal bones shoot forwaril beyond the mutilated edges 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 ex- 

 tent 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 Euminantia 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 connexion of the 

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



