1841.] Illustrations of the Genera of the Bovinos, 461 



more arched the forehead the obtuser the angle formed with the occipital 

 plane and the more distinctly do a portion of the frontals and all the 

 parietal go to from a part of that plane. In such cases the pseudo- 

 occipital portion of the posteal plane is very noticeable constituting 

 nearly one half of its whole depth and representing a transverse ovoid 

 figure or oblate spheroid bounded above by the vaguely denned crown 

 of the frontals, and below by the rather deep indentations of the temporal 

 fossae connected by any imaginary line. But usually, and whenever 

 the frontals are not very much curved in their length, the pseudo-occipital 

 portion of the posteal plane of the scull is trivial in depth, and denned 

 above by a nearly straight line between the ends of the horns — the rest 

 of the posteal plane constituting a second and less depressed sphere, 

 defined above by the course of the true occipitalr idge, and nearly exclud- 

 ing the parietal trigon so strongly marked in the last or the Bison of 

 Tibet, but here wholly unmarked, the bone itself being utterly merged in- 

 the frontals. 



In point of size the posteal plane of the scull, though moderate on the 

 whole, is yet usually larger than in the Ox or in the Yak, but far inferior 

 in extent to what is seen in Bibos — most nearly resembling the propor- 

 tion and figure too in the Gayal. The nasals, molars and intermaxil- 

 laries are extremely developed longitudinally, so that the orbits are 

 nearly twice as far from the symphysis intermaxill. as from the crown 

 of the frontals. These bones have no proportionate breadth so that the 

 face is narrow as well as long, except at the symphysis of the intermaxil- 

 laries where the dilation of the bones clearly indicates the broad massive 

 muzzle of the live animal. The intermaxillaries intervene between the 

 molars and nasals for 2 to 3 inches : the nasals are not at all arched and 

 are well produced to the front so that the nasal cavity is upon the whole 

 small, though somewhat increased by the lateral dilatation of the intermax- 

 illaries in the region of the muzzle. The deficient width of the scull 

 is indicated by the close position of the rami of the lower jaw T , and 

 its moderate height or depth, by their small curvature, though in the 

 last particulars of deficient depth and consequent straightness of the 

 lower jaws, the Yak's scull is pre-eminent. The horns of the Arna 

 are signally remarkable for size, for horizontality, and for depression : 

 their thickness is not so remarkable as their length and their tendency 

 backwards parallelly to the plane of the face with bold lateral single 

 curves (to the sides neither sinking nor rising) and more or less of 

 divergency. Their length is sometimes enormous and there is a clear 

 distinction between the breeds with the longer and less divergent, and 



