802 



THE UNGULATES, OR HOOFED MAMMALS 



the former are large, and frequently extremely massive at the base, those of the 

 latter are small and narrow. In the males the horns are generally more or less trian- 

 gular in section, and marked by parallel transverse wrinkles, while their color is 

 greenish or brownish; they are directed outwardly from the sides of the head, their 

 upper border being at first always convex, and the curvature generally taking the 

 form of an open spiral, with the tips turned outward. The face has generally, but 

 not always, a small gland below the eye, and there is a corresponding depression in 

 the skull for its reception; and the muzzle differs from that of the 

 oxen in being pointed and covered with short hair. Another dis- 

 tinctive feature of the group is the presence of a small gland in 

 each foot between the hoofs; and the females have but two teats 

 in place of the four of the oxen. The males of all sheep are devoid 

 of any strong odor; neither have they any beard on the chin. As a 

 rule, in wild species, the tail is very short; but in one case it 

 reaches just below the hocks. The ears are of moderate length; 

 and the hair, in wild species, is short and stiff, although it may be 

 elongated on the throat and fore-quarters. The upper molar teeth 

 differ from those of the oxen in having narrow crowns without any 

 additional column on the inner side. The feet have only the upper 

 ends of the lateral metacarpal and metatarsal bones remaining. 



As regards the characteristics of their molar teeth, the sheep 

 BONES OF THE resem ble the gazelles, and it is accordingly not improbable that 



LEFT FORE-FOOT . 



they may trace their descent to extinct antelopes, more or less 



\Jr 1 1 1 J 1 , brlrVx*,!^. 



(From Dawkins.) nearly allied to that group. Oxen, on the other hand, having 

 molar teeth nearly similar to those of the sable antelope and oryx, 

 may be more nearly allied to the ancestors of that group. 



Sheep are represented at the present day by eleven wild species, 

 which are mostly inhabitants of Europe and Asia northward of the 

 outer range of the Himalayas ; although one species occurs in the Punj ab and Sind , a sec- 

 ond in Northern Africa, and a third in North America. They associate either in parties 

 of two or three individuals, or in flocks of considerable size; and are essentially 

 mountain animals. Very generally, however, sheep inhabit the more open mountain 

 districts, rather than the craggy and steeply-scarped regions selected by the goats. 

 Most of the species are very nearly related to one another, and in several in- 

 stances it is difficult to determine whether certain forms ought to be regarded as 

 distinct species or merely as local races. Geologically, the sheep are even a more 

 modern group than the oxen, none of them being definitely known to occur before 

 the epoch of the so-called forest bed of the Norfolk coast, which belongs to the 

 upper part of the Pliocene or the lower part of the Pleistocene period. 



Distribution 



THE AMERICAN AND KAMCHATKAN WILD SHEEP ( Ovis canadensis 



and O. nivicola') 



The American wild sheep or ' ' bighorn " ( O. canadensis} and the Kamchatkan 

 wild sheep (O. nivicola) are two very closely-allied species, differing in several 



