SHEEP. 



213 



triangular in section, and marked by parallel transverse wrinkles, while their colour 

 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 outwards. 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 distinctive 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 odour ; 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 characters of their molar teeth, the sheep bones op the left 



resemble the gazelles, and it is accordingly not improbable that fore-foot of the 

 , . , 1 sheep. — From 



they may trace their descent to extinct antelopes more or less 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 northwards of the 

 outer range of the Himalaya ; although one species occurs in the Punjab and Sind, 

 a second 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 

 instances 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 Kamschatkan Wild Sheep (Ovis canadensis 



and 0. nivicola). 



The American wild sheep or " bighorn " (0. canadensis) and the Kamschatkan 

 wild sheep (0. nivicola) are two very closely-allied species, differing in several 

 important respects from the other members of the genus. The most distinctive 



