149—62 CEANIA OP RUMINANTS PROM THE INDIAN TERTIARIES. 
in both the molars have an accessory median column ; the skull of Tragonerus, 
hovrever, is distinguished by having the horn-cores placed more immediately over 
the orbits, by their cross-section being ellipsoidal, and by the general shortness of 
the face. 
Turning now to the true goats and comparing the crania of the two species of 
Hemitragus with the cranium of Hemihos, we find that in both genera the plane of 
the occiput forms an acute angle with the plane of the frontals ; in both the inter- 
cornual ridge is situated above the superior border of the orbit ; while in both 
the horn-cores are triangular in cross section, and have their anterior border con- 
tinuous with the plane of the frontals, and the parietals form a distinct transverse 
band across the skull behind the horn-cores. In both the horn-cores are approxi- 
mated to the orbits, and the su]3ra-orbital foramina have the same general position 
and relations ; the horn-cores of Semihos are, however, much wider apart at their 
bases than in any living goat, and are also distinguished by being straight. 
The cranium of Semihos^ again, differs from that of any existing species 
of goat, in that the plane of that part of the frontals which is below the horn- 
cores forms an obtuse angle with the plane of the parietals and of that portion 
of the frontals which is behind or above the horn-cores ; whereas in the goats and 
their alhes these two planes are placed at right angles to each other. 
Again, the presence of the median accessory tubercle in the molars of Semihos 
separates the cranium of that genus from the crania of all recent goats ; this acces- 
sory tubercle occurs in the molars of all the oxen, and in those of the larger deer ; it 
is generally absent in the antelopes, but is found in the uj)per molars of the 
Gnu, and in those of Antilope hoodon, and of Tragocerus amaltheus of the European 
Miocene ; it is entirely absent in all species of goats and sheep. 
Turning now to the basi-occipital of Semihos, we find that this bone is wedge- 
shaped, and therefore is more Bovine that Antilopine or Caprine in character ; the 
posterior paff of tubercles are considerably the larger of the two, and are separated by 
only a small interval from the occipital condyles, as in the oxen ; the median groove, 
however, between the tubercles of either side is deeper than in the oxen, and more 
hke the same part in the antelopes ; in the latter group, however, and in the goats, 
the basi-occipital is wide and quadrate in shape, both pairs of tubercles are well 
marked, but the anterior pair are generally the larger of the two, and the interval 
between the two tubercles of opposite sides is nearly uniform ; in the goats there 
is a considerable interval between the hinder pair of tubercles and the occipital 
condyles. 
The nasals of Semihos are narrow inferiorly, and taper to a point as in the 
goats and antelopes. 
On the whole, it appears that Semihos presents characters intermediate between 
the oxen on the one hand and the goats and the antelopes on the other, but that 
the majority of its affinities are with the oxen ; while in the form of the horn-cores 
it is distinct from all. 
