OXEN. 185 
It is stated by Blyth that in old bulls the skin between the bases of the horns 
becomes enormously thickened, and assumes a horny and rugged condition; this 
development beginning to take place before the coat has commenced to change from 
the ight to the dark colour. 
The extinct Etruscan ox (B. etruscus) from the Pliocene of the European 
continent, appears to have been allied to the banting, but with the horns placed 
low down on the skull near the eyes. 
THE YAK (Bos grunniens). 
The yak is one of the numerous mammals peculiar to the elevated plateau of 
Tibet, and differs markedly from all the other members of the ox tribe, although to 
a certain extent it forms a connecting link between the preceding group and the 
bisons. The most distinctive peculiarity of the yak, so far as external features are 
concerned, is the mass of long hair with which the flanks, limbs, and tail are 
clothed, and which makes the general appearance of the animal so very different 
from that of other oxen. On the head and upper-parts of the body the hair is 
short and nearly smooth, and the long hair only commences on the lower part of 
the sides where it forms a fringe of great depth, extending forwards across the 
shoulders and backwards on to the thighs. On the tail the long hair is developed 
on the lower half, where it expands into an enormous tuft which does not 
generally reach below the hocks. There is also a tuft of long hair on the breast. 
The colour of the hair is a uniform dark blackish brown, sometimes tending to a 
rusty tint on the flanks and back, and with a grey grizzle on the upper part of the 
head and neck in very old individuals. Around the muzzle there is a little 
white. We frequently find the yak represented as a brown and white, or even a 
pure white animal, but all such specimens are domesticated, and mostly hybrid 
individuals. 
In build the yak is massively formed, with short and stout legs. The 
shoulders are high, but there is not the distinct ridge on the back characteristic of 
the gaur, and the whole back is nearly straight throughout, without any falling 
away at the hips. Both the ears and the muzzle are small; and the dewlap is 
totally wanting. The head is long and narrow, with a nearly flat forehead, and the 
eyes are approximated to the horns. The horns, which are very large in the bull, 
are smooth, and nearly or quite cylindrical, with the first curvature of their upper 
border concave, as in the gaur and banting. They curve at first upwards and out- 
wards, then sweep boldly forwards, after which they incline upwards and inwards, 
and in some cases slightly backwards. The hoofs are relatively large and rounded. 
In height, it is stated that old bulls occasionally stand nearly 6 feet at the 
shoulder; but 5 feet 6 inches may be taken as the average. The weight of 
bulls is said to be about 1200 Ibs. Average-sized horns vary in length from 
25 to 30 inches measured along the curve; but a pair has been recorded 
measuring 40 inches in length, with a basal girth of nearly 19 inches. The horns 
of the cows are always smaller and thinner than those of bulls. 
Such are the leading external characteristics of the yak; but there are also 
certain features connected with the skeleton which are worthy of notice. In the 
