352 BRITISH MAMMALS 



I do not find myself quite in agreement with the authorities on 

 these points. In the first place, from the little we know of the 

 geological age of oxen, sheep, and goats, the oxen appear to be 

 older than the last two named ; and though specialised in some 

 directions, they retain in others distinctly primitive features. 

 The cannon bones of front and hind legs (especially in the 

 front) are decidedly short, and they are divided down the 

 middle by so distinct and deep a groove as to be almost two 

 distinct bones, instead of being completely fused into one, as is 

 the case with the sheep and goats, the musk ox, and most 

 antelopes. Even in the deer the original division in the cannon 

 bone is only faintly indicated. The mammae, also, instead of 

 being only four, as in the deer, or two, as in so many sheep and 

 antelopes, are practically six in number. Only four are functional 

 teats, but on the udders of most cows there are two additional 

 mammae not normally functional. In this there would seem to 

 be some slight approximation towards the condition of the swine 

 (as examples of primitive Artiodactyles), in which there are six 

 to ten mammae. The tail in oxen is invariably long also a 

 primitive feature. In the most archaic of living oxen, the 

 Anoa and Tamarau buffaloes, there are indications of the white 

 spots, gorgets, and other markings of the primitive Artiodactyles ; 

 and though these are not developed anything like as much 

 as in the Deer and Tragelaphs, yet in the Capricorns, 

 Goats, Sheep, and Antelopes they have absolutely disappeared. 

 The horns of oxen do not display any sign of regular annu- 

 lation, which is characteristic of all the other groups of the 

 Bovid< except the Tragelaphs. Indeed, in the structure of 

 their horns they offer, perhaps, slightly more approximation 

 to the Tragelaphs than to any other of their relations. In 

 the last named, especially in an archaic form like the nilghai, 

 there is a tendency towards the development of triangular 

 twisted horns, in which the angle facing the front is often deve- 

 loped into a strong ridge. This three-cornered, and perhaps 

 slightly twisted, type of horn is characteristic of the earliest 

 known or most primitive of living oxen (Leptobos, Amphibos, 



