THE BISON. 



611 



others as a musk sheep ( Ovibos priscus Rtttimeyer). If this 

 is the ease the musk sheep, or a species closely allied to it," 

 formerly extended to the Middle States at or near the close 

 of the glacial period. 



"We now come to the bison and ox. The American bison 



Fig. 530. — Rocky Mountain Sheep or Big-Horn. — From Brehm's Thierleben. 



{Bison Americanus G-melin) formerly ranged from Virginia 

 and Lake Ohamplain to Florida, and westward from the 

 northern limit of trees to the Rocky Mountains and eastern 

 Mexico. It is now in danger of extermination, being mainly 

 restricted to a few herds on the plains. It is closely 



