406 BULLETIN OF THE 



dian Fauna forms the northern limit of the reptiles proper, where this 

 class is represented by two orders only, the Tesludinata and the Ophi- 

 dia The Testudinuta are there represented by only three species 

 (C/ielydra serpentina, Glyptemys inscidpta, Chrysemys picta), and the 

 Op/tidin by five (Baseanion constrictor, Tropidonotus sirtalis, Diadophis 

 punctatus, Storeria occipito-maeidata). In the Alleghanian Fauna the 

 number of species in each of these groups is more than doubled. The 

 Carolinian Fauna forms the northern limit of the Sauria, of which two 

 species {Plesliodon fasciatus, Tropidolepis undulalus) here first make 

 their appearance, and the number of species of the other groups is 

 still further increased, several additional generic types being added. 

 In the Louisianian Fauna the number of species of Sauria becomes 

 considerably greater, and while few of the northern species of either 

 the true reptiles or the batrachians have disappeared, other more 

 southern forms have been added in almost every family. 



These several faunae, it may be added, seem in general to coincide 

 in their number and limits with the florae of the same region. These 

 several flora?, as thus circumscribed, form successively the northern 

 limit of the successful cultivation of some more or less important cul- 

 tivated plant. But a detailed consideration of the distribution of the 

 vegetation of the region under consideration, in respect to the number 

 and circumscription of the flora?, and their correspondence with the 

 fauna?., cannot of course well be here introduced. 



4. The Ornithological Districts of the North American 

 Temperate Region. 



The subdivision by Professor Dana of the tropical and temperate 

 climatic zones of the oceanic areas into several zoological zones has 

 been already alluded to as being equally applicable to the land areas. 

 To these life zones I propose to apply the term "districts." Dana's 

 divisions of the north temperate climatic zone correspond respectively 

 in latitudinal extent with the several ornithological faunae of the 

 Fastern Province, as defined in the preceding pages. Unlike tie 

 fauna?, however, the districts extend in an east and west direction across 

 the North American Region, each district embracing not only one oi 

 the fauna? of the Fastern Province, but also its representative fauna (or 

 fauna?) in the Western Province. The Hudeonian Fauna corresponds 

 in latitudinal extent with Dana's subfri"id division of the north tern- 



