CHAP. IV.] ZOOLOGICAL REGIONS. 71 



are, for our present purpose, of much less importance. As a 

 primary division the "Arctic region" woukl be out of all pro- 

 portion to the other six, whether as regards its few peculiar 

 types or the limited number of forms and species actually in- 

 habiting it ; but it comes in well as a connecting link between 

 two regions, where the peculiar forms of both are specially modi- 

 fied ; and is in this respect quite analogous to the great desert 

 zone above referred to. 



I now proceed to characterize briefly the six regions adopted 

 in the present work, together with the sub-regions into which 

 they may be most conveniently and naturally divided, as shown 

 in our general map. 



Palccardic Eegion. — Tliis very extensive region comprises all 

 temperate Europe and Asia, from Iceland to Behring's Straits and 

 from the Azores to Japan. Its southern boundary is some- 

 what indefinite, but it seems advisable to comprise in it all 

 the extra- tropical part of the Sahara and Arabia, and all 

 Persia, Cabul, and Beloochistan to the Indus. It comes down 

 to a little below the upper limit of forests in the Himalayas) 

 and includes the larger northern half of China, not quite so 

 far down the coast as Amoy. It has been said that this 

 region differs from the Oriental by negative characters only ; a 

 host of tropical families and genera being absent, while there is 

 little or nothing but peculiar species to characterize it abso- 

 lutely. This however is not true. The Palasarctic region is well 

 characterized by possessing 3 families of vertebrata peculiar 

 to it, as well as 35 peculiar genera of mammalia, and 57 

 of birds, constituting about one-third of the total number it 

 possesses. These are amply sufficient to characterize a region 

 positively ; but we must also consider the absence of many im- 

 portant groups of the Oriental, Ethiopian, and Nearctic regions ; 

 and we shall then find, that taking positive and negative 

 characters together, and making some allowance for the neces- 

 sary poverty of a temperate as compared with tropical regions, 

 the Palaiarctic is almost as strongly marked and well defined as 

 any other. 



Sub-divisions of the Palarirdic Eegion. — These are by no means 



