CHAP. XV.] THE NEARCTIC EEGION. 119 



tomed to consider as typically EuroDean, or Palaearctic, having 

 representatives in North America ; ^though in many cases it 

 would be more correct to say that they are Nearctic genera, 

 represented in Europe, since America possesses more species 

 than Europe or North Asia. The following is a list of genera 

 which have as much right to be considered typically Nearctic 

 as Palaearctic : — 



The seven genera italicized have a decided preponderance of 

 Nearctic species, and have every right to be considered typically 

 Nearctic ; while the remainder are so well represented by peculiar 

 species, that it is quite possible many of them may have origi- 

 nated here, rather than in the Palaearctic region, all alike being 

 quite foreign to the Neotropical. 



On the whole, then, we have 47 in the first and 7 in the second 

 table, making 54 genera which we may fkirly class as typically 

 Nearctic, out of a total of 168 genera of land- birds, or nearly 

 one-third of the whole. This is an amount of peculiarity which 

 is comparable with that of either of the less isolated regions ; 

 and, combined with the more marked and more exclusively 

 peculiar forms in the other orders of vertebrates, fully establishes 

 Temperate North America as a region, distinct alike from the 

 Neotropical and the Palaearctic. 



Reptiles. — Although temperate climates are always compara- 

 tively poor in reptiles, a considerable number of genera are 

 peculiar to the Nearctic region. Of snakes, there are, Conophis, 

 Chilomeniscus, Pituophis, and Ischnognathus, belonging to the 

 Colubridse; Farancia, and Dimodes, Homalopsidae ; Lichanotus, 

 one of the Pythonidae; Cenchris, Crotalophorus, Uropsophorus, 

 and Crotalus, belonging to the Crotalidae or rattlesnakes. 



Of Lizards, Chirotes, forming a peculiar family ; OpMsaunis, 



Vol. II.— 9 



