4i8 



DISTRIBUTION IN SPACE AND TIME 



ing nearly 300 species, is almost wholly confined to this region, 

 and would alone serve to distinguish it zoologically from all other 

 parts of the globe". 



Fauna of the Nearctic Region. — It will be remembered 

 that the " holarctic " forms already mentioned are common to 

 the Palcearctic region and northern part of the Nearctic region, 

 and need not, therefore, be mentioned again, though it may be 

 well to state that the Musk- Ox {Ovibos) is almost entirely 



Nearctic. 



Nearctic Mammals 

 {Mammalia). — Among 

 the Insect- Eaters (/w- 

 sectivora) the Star - 

 nosed Mole {Coiidy- 

 hira, fig. 1288) is the 

 most remarkable of 

 the purely Nearctic 

 forms. A number of 

 the Flesh- Eaters {Car- 

 nivora) differ from 

 those of the Old 

 World, but as the most 

 important of these are 

 even more character- 

 istic of the Neotropical 

 region, mention of 

 them will be post- 

 poned. Two of the Hoofed Mammals {Uugztlata) are essentially 

 Nearctic, i.e. the Pronghorn [Aniilocapra) and the Rocky Moun- 

 tain Goat {Haploccros). Two families of Gnawers {Rodentia) are 

 confined to this region, the Pouched Rats {Saccomyidcr), including 

 Gophers, Kangaroo- Rats, and Pocket- Mice, and the Sevvellels 

 [Haplodo7itidcs), including two species of small rodents allied to 

 the squirrels but with the habits of marmots. Besides these, two 

 very typical Nearctic genera belong to this order, i.e. those to 

 which the Tree- Porcupine {Erel/iizoii) and the Prairie- Dogs 

 {Cyiiomys) belong. Opossums {Didelpliyidce) represent the 

 Pouched Mammals (Maisipialia) in this region, but are more 

 typical of the Neotropical. 



Nearctic Birds (Az'es). — Many of the familiar Palasarctic 



C Olid y I lira) 



