32 HOOFED ANIMALS 



genus Ovis in its progress southward. At Pinacate and the 

 Seri Mountains it is stopped by aridity, heat, thirst and the 

 general scarcity of food. In 1907 we collected several speci- 

 mens on the awful lava-fields of Pinacate, and we found that 

 there the robust Big-Horn of the North had greatly diminished 

 in size. The rams measured only 37 inches in shoulder height, 

 which is from 3 to 4 inches below the normal height farther 

 north. The legs were short, and delicately formed, the hoofs 

 were small, the pelage was very short and thin and the weight 

 of rams was about 30 per cent under the average figures for 

 northern adult animals. 



Southward of the range of the Big-Horn are found three 

 new species which appear to be offshoots of it. In southern 

 California is found the California or Nelson's Mountain 

 Sheep, 1 a smaller animal than the big-horn, short-haired, and 

 of a pale salmon-gray color. On the peninsula of Lower Cal- 

 ifornia there is to be found— if looked for during the next five 

 years — a short-haired, large-horned species that has been 

 described as Ovis cremnobates. Of this species some fine heads 

 exist in New York and Philadelphia collections of big-game 

 heads. 



In the state of Chihuahua, Mexico, is found the Mex- 

 ican Mountain Sheep, 2 in color much like the Californian 

 species, but larger, and with large ears. The horns some- 

 times measure 16 1 ? inches in basal circumference. This 

 species is now almost, if not quite, extinct. 



The White Mountain Sheep, or Dale's Sheep, 3 of 

 Alaska, discovered and described by E. W. Nelson in 1884, 



1 O'vis nel'son-i. 2 O'vis mc.v-i-caii'us. ■ 3 O'vis dall'i. 



