212 



THE AMERICAN NATURALIST 



[Vol. XLl 



merits in the district; or, if interbreeding suffices to reduce the 

 diversity in some degree, at least several kinds perferring different 

 hal)itats. While in the broader geographic sense this effect 

 would be polyty})ic, in that any geographic district nnght have 

 several different closely allied types, each type would fit a partic- 

 ular set of conditions; there would be definite allotment and 

 topographical separation of the derivative species, and each 

 ecological field would present a monotypic aspect. A distribu- 

 tion quite distinct from that due to recent Mutation would be 



Thus while the geography of species may or may not be deci- 

 sive as between the evolutionarv theories known by the names 

 Natural Selection and Orthogenesis, both those modes are dis- 

 tinguished from IMutatioii in the unincdiaK' cllects winch they 

 have upon distribution. >Sn(h sjx'cific (hstnbntion as Moritz 

 Wagner asserted to be ninvcrsal or almost nnivcrsal. li it could 

 he pro\ed, would be piadualK t ital tc the MiMation Theory 

 regarded as a general explanation ot .sjx'cilic evolution.' 



the competence of geographic evidence. Indeed the\ appear 

 at times to recognize the propriety of the appeal to nam re; 1 )e 

 ^^les refers to Draba, Viola ami similar gM.ii|.. iiid Ma< Doii-al 

 in the paper alreadv cited alludes to stiidi.>s of [.lant distribution 

 and addiKo tin (an ot <I.>mK idand Opiintia. in tlu Vn/ona 

 <leMMt llu <li^tinun>h(d /o<.lo^i.t ^^\^u u(UitK ...iitned to 

 pass upon the merits of the Mutation Theorv, (evidently without 



' let Danviii (Oris. Hp., eh. IV.) in his theory of Divergence of Chanxcter, 



