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 light 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 



