XI 



THE PAL^ARCTIC AND NEARCTIC REGIONS 



237 



aTid Mxtinct. In the case of the birds, I am indebted 

 to my friend Mr. H. E. Dresser, both for completing his 

 List of Euo'opean Birds so as to include those of the 

 whole Palsearctic region, and also for so harmonising his 

 genera with those of the A. 0. If. Check List of North 

 American Birds as to combine the whole into a single 

 series. As Mr. Dresser has made a study of North Ameri- 

 can birds as well as of those of the Palsearctic Region with 

 which his name is more especially associated, the result is 

 probably as fair and unbiassed, for the comparison in 

 question, as can be arrived at. In the case of both 

 regions, I have rejected all those genera in which a single 

 species only just enters the region from the adjacent 

 region to w^hich it properly belongs. Here, again, there 

 is, of course, room for difference of opinion ; but the 

 doubtful cases are not sufficiently numerous to introduce 

 any important uncertainty into the result. 



For both mammals and birds I adopt the same system 

 of presenting the facts which, after much consideration 

 and many trials, seems to me to be the best. The families 

 and genera are arranged in three columns — the first giving 

 those which are Palsearctic but not Nearctic; the third 

 those that are Nearctic but not Palaearctic ; the middle 

 column giving those which are common to the tw^o regions 

 — so that by combining this with either of the others we 

 obtain the entire fauna of that region. The results are 

 then summarised in other tables and briefly discussed. 

 We begin with the mammals : — 



MAMMALS OF THE PAL^ARCTIC AND NEARCTIC REGIONS. 



