127—40 CEANIA OE EUMINANTS PROM THE INDIAN TERTIARIES. 
The living genus Poephagus is now confined to the highlands of Tibet, and is 
seldom found much below an elevation of fifteen thousand feet. It becomes an 
interesting question to consider whether the allied fossil species was an inhabitant of 
the plains or of elevated land. I am inclined to think that it most probably was 
a dweller on the plains or low hills, because, with the exception of a few species of 
goats and sheep, all the Siwalik mammalia were plain-dwelling forms, and it is 
improbable that there was at any rate much elevated country within the old 
Siwalik area ; moreover, the Bison of America and the Bison of Europe are both 
j)lain-dwelling forms. A very probable theory is that the fossil Bison of the 
Siwaliks dwelt on or near the plains, and from some cause or other in later times was 
induced to migrate into more and more hilly country, until finally it gave rise to 
the modern Yak, which cannot exist except in the rarified atmosphere of highland 
Tibet ; at the same time the occurrence of a true Ibex, as recorded by the late 
Mr. Blyth,' in the Siwaliks, might give us grounds for taking an exactly opposite 
view of the case. 
Genus BUBALUS. 
Tlie cranium of this genus may be defined as follows : — Horn-cores placed 
below the plane of the occiput, frequently triangular, forehead convex — broader 
than long, nasals very large and wide, occiput rounded superiorly, and with distinct 
indentations of the temporal fossge ; the superior border of the horn-cores concave. 
Bubalus platyceros, n. sp. nohis. Plate 18. 
It is with some difiidence that I refer the present species to the genus Bubahis, 
the cranium on which it is founded being aberrant in many points from any modern 
type forms. I rely, however, chiefly on the form of the occipital surface and the 
shape of the horn-cores, both of which are clearly Buhaline in the present speci- 
men. The form of the occipital surface and its relation to the intercornual ridge 
appears to afford the most dependable characters in dividing the Bovina. 
The cranium of which I have given two views is another specimen from 
Mr. Theobald’s Siwalik collection. The greater part of the forehead and the upper 
half of the face are tolerably perfect ; the zygomatic arches, the lower portions of the 
orbits, the distal half of the nasals, the premaxillse, and the whole of the spheno- 
palatine regions of the skull, are wanting ; the occipital region shews only the 
smooth supra-cristal portion, with a small part of the inferior surface for muscular 
attachments and the temporal fossae ; this remaining portion is, however, fortunately 
characteristic. The greater portion of the right horn-core remains, and a large 
detached fragment of the upper half of the left core was found with the specimen ; 
this has been put into its proper position in the figure. 
• Ann.- Mag. Nat. Hist. Ser. I, Vol. XI, p. 78. 
