No. 487] 



473 



Ohio, and he uotvd that oc. asioiially, as at Cabhi John Bridge, Md., 

 in 1900, sports are relalivel.v v.mv abundant. . . .If 1 had been so fortu- 



eonehisions, and h^^c .U|.|>..r1cd the inut:Ui(>n tlieorynmst 



loyally...." 



Aifjner-Ahafi (Ann. // /.v/.-.V,//. M .\nf. limn/., 1: Isl .-,;^1,1900) 



Porritt {Rep. Brit. Ass., 7i\: :Ui-y-XV2, 1907) ha.s (riven a detailed 

 aecount of the increa.se of melanism in Yorkshire U'{)i(h)])tera. The 

 author confines liimself strictly to recording the facts, some of which 

 seem to support the mutation theory although others do not. 



In all tliese ca.ses it is olrserved that zoologists are cautious about 



Biology in the Journal of Agricultural Science. .Mtlionuh the n al 



