VERTEBRATA: MAMMALIA. 721 



Nearly allied to the Aurochs is the American Bison or Buffalo (Bison 

 Ainericanus], This species formerly occurred in innumerable herds in the 

 prairies of North America, but it has been gradually driven westwards, 

 and has been much reduced in numbers. It has an enormous head, a 

 shaggy mane, and a conical hump between the shoulders. Two other 

 very well known forms are the Cape Buffalo (Bubalus caffer) and the 

 common Buffalo (Bubalus bubalis). The former of these occurs, with two 

 allied forms, in southern and eastern Africa, and the latter is domesticated 

 in India and in many parts of the south of Asia. The horns in both 

 species are of large size, and their bases are confluent, so that the forehead 

 is protected by a bony plate of considerable thickness. 



Amongst the more remarkable Asiatic Oxen may be mentioned the Zebu 

 (Bos Indicus] distinguished by the fatty hump over the withers at the back 

 of the neck, and the Yak (Poephagus grunniens] of Thibet, remarkable for 

 its long silky tail, and the possession of a fringe of long hair along its 

 shoulders, flanks, and thighs. The "humped" Cattle of the East are 

 almostly certainly descended from a stock different to that which has given 

 origin to the humpless races. They are known from Egyptian monuments 

 to have been domesticated at an extremely early period ; but their wild 

 form is unknown. 



The last of the Oxen which deserves notice is the curious Musk-ox 

 (Ovibos moschat^ls}. This singular animal is at the present day a native of 

 Arctic America, north of latitude 60, and is remarkable for the great 

 length of the hair. It is called the Musk-ox, because it gives out a musky 

 odour. Like the Reindeer, the Musk-ox had formerly a much wider geo- 

 graphical range than it has at present ; the conditions of climate which are 

 necessary for its existence having at that time extended over a very much 

 larger area than at present. The Musk-ox, in fact, in Post-tertiary times 

 is known to have extended over the greater part of Europe, remains of it 

 occurring abundantly in certain of the bone-caves of France. Good author- 

 ities regard the Musk-ox as being a sheep, and therefore truly referable to 

 the Ovidce. 



As regards the distribution of the Ungnlata in time, the 

 order is not known to have commenced its existence earlier 

 than the Eocene Tertiary ; but it presented itself throughout 

 the whole Tertiary period under such numerous and such 

 varied types that it will not be possible in this place to do 

 more than simply indicate the geological range of the principal 

 families. 



Of the Rhinocerotida, hornless forms (Acerotherium) occur in 

 Miocene and Pliocene strata ; but the best-known fossil species 

 is the two-horned Woolly Rhinoceros (R. tichorhinus). This 

 curious species occurs in Post-pliocene deposits, and must have 

 ranged over the greater part of Europe. It was adapted to a 

 temperate climate, and, like the Mammoth, possessed a thick 

 covering of mixed wool and hair. This has been demonstrated 

 by the discovery of a frozen carcass in Siberia. The curious 

 genus Diceratherium, with its transverse pairs of horns, is from 

 the Miocene of North America. 



The Tapiridce are represented in the Eocene and Miocene 



2 z 



