THE NAUTILUS. 59 



serious fault in the English work, that we were so little alert for 

 racial characters, and we were also to blame for confusing under the 

 name " variety " several different phenomena. I have watched the 

 development of the American researches with admiration, and cer- 

 tainly have no fault to find with the methods adopted; but at the 

 same time I believe we make a great mistake if we assume that 

 sporadic varieties are not worth noting and recording. Professor 

 Pilsbry will probably concede all this, in principle, but will object 

 to giving them names. It is unavoidable, I suppose, that there 

 should be differences of opinion about this; but it is certainly true 

 that only when they are named and find a place in the manuals do 

 they get properly noticed and recorded. 



The best example of the English method which has so far appeared 

 is found in Taylor's " Monograph of the Land and Freshwater Mol- 

 lusca of the British Isles," now in course of publication. I can 

 hardly believe that any naturalist can study this work without ad- 

 miring its exhaustive treatment of variation, and perceiving the 

 value, from the standpoint of evolution, of the orderly presentation 

 of so great a mass of information. At the same time, it is not with- 

 out its faults, one of which is the confusion together of different races 

 and mutations, treating them all as " varieties," without discrimina- 

 tion. Thus under Testacella scutulum, the geographical form major, 

 from Algeria, appears as a variety; while its mutation albino, is 

 made to include all pallid forms, whether from Algeria or elsewhere. 

 It is evident that albina should be treated under major as a muta- 

 tion ; and the name pallida, proposed for the pale mutation of the 

 typical scutulum, should be so applied. Following the Jeffreysian 

 method, the term " monstrosity " is applied in an illogical manner to 

 sinistral mutations and various distortions of the shell, which have 

 nothing particular in common. 



Deviations from the normal may be conveniently included under 

 three heads : 



1. Subspecies, as generally understood in this country ; forms oc- 

 cupying a distinct territory (or it may be ecological position) of their 

 own, but intergrading with the species. 



2. Mutations, the so-called spontaneous variations, arising sporad- 

 ically from some modification of the germ-plasm, and often persisting 

 in limited strains. These include, among other things, sinistral and 

 albino variations ; and it is desirable that analogous variations of 



