119—32 CRANIA OP RUMINANTS PROM THE INDIAN TERTIARIES. 
diameter of the carpal surface is 4-8 inches ; the form of all the specimens is the 
same ; and Dr. Palconer says that specimen No. S. 346 corresponds very closely 
with the same hone in Bos, differing only in its greater size. 
As there are a considerable number of metacarpal and metatarsal bones in our 
collections, differing slightly in size one from another, it becomes a question whether 
they should all be referred to Sivatlierium, or whether some of them may not really 
belong to Bos. In favoim of the latter view of the case it may be stated that, with 
the exception of these metacarpal and metatarsal bones, the bones of Sivatherium 
are of somewhat rare occurrence, while those of Bos are much commoner. 
If some of these bones could therefore be referred to the latter genus, it would 
render the proportionate number of these bones of the two genera more consonant 
with the number of crania. To decide this question it is necessary to find some 
correlation between the dimensions of the metacarpus and the cranium ; such a 
correlation I am at present unable to discover, which wMl prevail in all cases, the size 
of any particular portion of the cranium of the Bovina not always increasing in 
the same ratio with its general dimensions. 
In some cases, however, the width of the occiput does seem to be a fair 
criterion of size ; the diameter of this surface in Bihos gaurus is 8’1 inches, while 
the transverse diameter of the condyles of the metacarpus is 2‘8 inches ; in Bibos 
frontalis these two diameters are respectively 7’4 and 2'4 inches. The transverse 
diameter of the occiput of Bos aoutifrons is 11'4 inches, while the transverse diameter 
of the trochlear condyles of the present metacarpal is 4’4 inches. The proportion in 
all the above cases is therefore rather more than three to one ; and if the metacarpus 
varies in size in the same proportion as the occiput, the present metacarpus would 
not be too large to belong to Bos aoutifrons, under which head, as above said, I am 
disposed to place it. The bone is an inch wider and two inches longer than the 
metacarpal of Bos namadicus, and, if I am right in the position assigned to it, indicates 
that Bos aoutifrons is the largest known species of fossil ox. 
Bos PLATYRHINUS, n. sp., nobis. Plate 14. 
This species is founded upon the lower half of a cranium figured in the above 
plate. The specimen was collected by Mr. Theobald in the Siwahks of the Kangra 
district, and, though less complete than might have been desired, is yet of 
so peculiar a form that it cannot be referred to any of the foregoing species of 
Siwalik oxen. Unfortunately we do not possess the lower portions of the skulls of 
the above-described species, so that an exact comparison between them and our 
present species is impossible. The only portion that is common to the skulls of the 
three species is the portion about the orbits; that portion, however, is amply 
sufficient to distinguish them from each other. The specimen is broken off across 
the lower border of the orbits, apparently by a very recent fracture ; the portion 
which remains is very nearly perfect. 
