CHAP. XV.] 
THE NE ARCTIC REGION. 
129 
sub-region. It is allied to the European nutcracker ; but ac- 
cording to the American ornithologist Dr. Cones, has also resem- 
blances to the jays, and certainly forms a distinct genus. The 
grizzly bear ( Ursus ferox) in the background, is one of the 
characteristic animals of the Californian highlands. 
II. The Central , or Rocky Mountain Sub-region. 
This extensive district is, for the greater part of its extent, from 
2,000 to 5,000 feet above the sea, and is excessively arid ; and, 
except in the immediate vicinity of streams and on some of the 
higher slopes of the mountains, is almost wholly treeless. Its 
zoology is therefore peculiar. Many of the most characteristic 
genera and families of the Eastern States are absent ; while a 
number of curious desert and alpine forms give it a character 
of its own, and render it very interesting to the naturalist. 
Mammalia. — The remarkable prong-horned antelope ( Antilo - 
capra), the mountain goat (. Aplocerus ), the mountain sheep or 
bighorn ( Ovis montana), and the prairie-dog ( Cynomys ), one of 
the Eodentia, are peculiar to this sub-region ; while the family 
of the Saccomyidae, or pouched rats, is represented by many forms 
and is very characteristic. Here is also the chief home of the 
bison. The glutton (Gulo) and marmot (Lagomys) enter it from 
the north; while it has the racoon ( Procyon ), flying squirrel (Sciu- 
ropterus ), ground squirrel ( Tamias ), pouched marmot (Spermo- 
philus ) and jumping mouse {Jaculus) in common with the 
countries east or west of it. 
Plate XIX, Illustrative of the Zoology of the Central Plains or 
Prairies. — We here introduce four of the most characteristic 
mammalia of the great American plains or prairies, three of them 
being types confined to North America. The graceful animals on 
the left are the prong-horned antelopes ( Antilocapr'a americana ), 
whose small horns, though hollow like those of the ante- 
lopes, are shed annually like those of the deer. To the right 
we have the prairie-dogs of the trappers ( Cynomys ludovi- 
cianus) which, as will be easily seen, are rodents, and allied 
to the marmots of the European Alps. Their burrows are 
numerous on the prairies, and the manner in which they perch 
VOL. II. K 
