1841.] Illustrations of the Genera of the Bovince. 459 



the frontals on either side of it, the same plane in the Yak becomes trigo- 

 nal — or where the parietal ridge is more obscure and the rounded off and 

 transversely arched ridge line of the frontals is made to define the occipi- 

 tal plane superiorly — semicircular ; the base being always considered a 

 straight line. There is a strong tendency, no doubt towards the Bubaline 

 scull in the Yak, and not merely in the round and sloped off frontals as 

 as above noticed, but also in the great extent of the facial portion of the 

 scull, and in the very small curve of the rami of the lower jaw. Towards 

 Bibos again there is an inclination in the transverse intercornual arch 

 though it be vague, in the salient orbits, and in the longitudinal arcua- 

 tion of the nasals, as well as in the large lateral vacuity towards the 

 molars. The intermaxillaries cease considerably short of the nasals and 

 the two sets of bones are consequently wholly unconnected, more so even 

 than in the Gouri or Gayal. The nasals are no way deficient in length ; 

 yet is the interval between their anteal extremities and those of the in 

 termaxillaries more signal than in the Gouri, the Gayal, or even the Arna 

 in which last the nasals are at a maximum of developement so as to be 

 connected with the intermaxillaries for a considerable extent — a circum- 

 stance sometimes observable to a less extent in the sculls of the common 

 Ox. In the living Bison or Yak the muzzle is small as in Bibos, but I 

 cannot say I clearly trace the symptoms of this in any unusually narrow- 

 ness of the intermaxillaries at their symphysis. Upon the whole the sculi 

 of the Yak as compared with that of the common Ox, is larger in propor- 

 tion to the size of the animals, and exceeds the Bovine scull as much in 

 breadth as it falls short of it in depth or height. These are characters of 

 depression and are no where else so noticeable as in Bibos (excluding the 

 crest) whence the sculls of both come further to agree in the common in- 

 clination towards straight lower jaws lowly articulated. But in the 

 length of the facial portion of the scull as compared to the frontal 

 and consequent high position of the orbits, and in the tendency of 

 the rounded frontals to slope off easily towards the occipital plane, 

 the Yak's scull differs antipodally from that of Bibos, approaching 

 in the same degree to the Bubaline cranium. Of all the sculls now 

 before us the position of the orbits is highest (longitudinally viewed) 

 in the Arna or wild buffalse, and lowest in the wild Gouri or Bibos ; 

 in the Yak its position is most analogous to that it holds in the common 

 Ox. In regard to saliency of the orbits, there is the strongest resem- 

 blance between the Bison and Bibos — none of the others showing the 

 least tendency that way. The horns of the yak, of moderate size, jetty 

 black, rounded and smooth occupy, as usual, the ends of the frontal 



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