32 
THE OX AND ITS KINDRED 
larger species of buffalo, the other being Indian. 
The group was undoubtedly of Old World origin, the 
American bison and its extinct relatives being 
comparatively recent immigrants into the New World, 
which they reached by means of a land - bridge in 
the neighbourhood of what is now Bering Strait. 
Geologically the oxen are a comparatively modern 
group, their oldest known representatives occurring 
in the Lower Pliocene rocks of the Siwalik Hills of 
northern India, in which they are represented by 
species more or less nearly related to the typical ox, 
and by others akin to the dwarf buffalo, or anoa, of 
Celebes. In the succeeding Lower Pleistocene rocks 
of the valley of the Narbada occur oxen characterised 
by their slender build, the low relative position of the 
horns on the skulls of the bulls, and the absence of 
these appendages in the cows, both these features 
indicating an approximation to antelopes. Another 
representative of these oxen with hornless females, 
which constitute the subgenus Leptobos^ has left its 
remains in the Pliocene strata of the Val d'Arno, 
Italy. 
In regard to the nearest living relatives of the oxen 
group, it is practically certain that these are to be 
sought among the antelopes. 
The remarkable resemblance existing between the 
horns of the African gnus, more especially the 
brindled or blue species {ConnocJioetes taurinus), and 
those of cattle, has frequently formed the subject of 
comment, although the general opinion has been to 
the effect that this resemblance is not indicative of 
close genetic affinity between the two groups. The 
case is, however, somewhat altered by investigations 
into the anatomy of the soft parts of ruminants 
