SOME PROBLEMS OF TAXONOMY 
295 
most conspicuously in the Indian fauna of the wet and dry sea- 
sons, but quite evidently in the various forms of P. napi Linn. 
Aberrations are known to every systematist and the name is self 
explanatory. Varieties have been confusing in that the term has 
been made to include everything not nimotypical. In the check 
list mentioned the terms form and race have been substituted for 
variety. A form is regarded as a variation occurring side by side 
with the nimotypical form, in contrast with geographical races, 
which are variations occurring in a region distinct from that oc- 
cupied by the nimotypical form. This substitution seems to be 
so successful that it permits the discarding of variety as an obso- 
lete term. In order to present the consideration of these sub- 
divisions more graphically I have drawn diagram A, assuming 
