Dr. N. SevertzofF on the Mammals of Turkestan. 333 



tatives of this species. Marco Polo talks about some larger 

 sheep from the higher-situated plains at the summits of the 

 mountains at the Kashgar-Darja, and M. SemenofF says 

 that the sheep seen by him about Han-tengri were as large as 

 a stag — that is, not less than 7 feet in length, and over 4 feet 

 high at the shoulders. 



It is therefore probable that the very nourishing food and 

 the rarefied mountain-air had also some influence in the con- 

 tinual development of the sheep in their size and their horns. 



The rarefied and cold mountain-air generally enlarges the 

 proportions ; this is not only the case among the mammals but 

 also some birds : for example, Gyps nivicola is much larger 

 than G. fulvus ; also G. harhatus grows larger in proportion 

 to the altitude of the locality it inhabits. Of course some 

 circumstance might exist which would interfere with the 

 growth of the sheep — as, for instance, want of food in the 

 high mountains, as in the case of 0. onontano, of the Rocky 

 Mountains of North America, which is smaller than 0. argali^ 

 although it inhabits higher localities ; but this does not at 

 all disprove ray theory as to the influence of the mountain-air 

 on the growth of the sheep ; for in Asia the high-elevated 

 hills are never or very seldom covered with snow, and 

 therefore the winter food is abundant, whilst the Rocky 

 Mountains are covered with snow, and in consequence the 

 sheep suff'er from want of food. 



In conclusion, I will only add that very little further mate- 

 rial exists to settle the question regarding the origin of the 

 wild and tame sheep of Central Asia, because of the unfavour- 

 able conditions for the preservation of the skulls which are 

 scattered in the mountains. 



On the ground these skulls very soon get spoiled : the bones 

 get soaked in the snow, and then again very dry in the 

 summer ; and in consequence they soon rot. I found them 

 in all stages of decomposition, and some even with part of 

 the horns fallen off. Complete skulls could only be preserved 

 in some dried- up lake ; but, judging from the animals' habits, 

 the skulls are not likely to get there. Therefore it is not at 

 all premature to try and complete as far as possible the evi- 

 dence of the origin and development of the different species 

 of sheep which exist at the present time. 



71. Capra sihirica. 



Is pretty common in the eastern portion of Turkestan, par- 

 ticularly in the higher regions of the Thian-Shan mountains, 

 where it never descends below 4500 feet above the sea. 



