CHAP. XV.] THE NEARCTIC REGION. 129 



sub-region. It is allied to the European nutcracker ; but ao- 

 cordiug to the American ornithologist, Dr. Coues, 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. 



//. 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 Saccomyidse, 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 (Frocyon), 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 (Antilocapra 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 



