60 THE NAUTILUS. 



different species should receive the same mutational name : e. g., 

 sinistrorsuTti for all sinistral mutations. 



The interest attaching to these variations is very great at the 

 present time, when so much is being said about the theories of de 

 Vries and the Mendelian phenomena. We have, moreover, pretty 

 good evidence that such " sports " have given rise to genuine specific 

 characters, certain shells (e. g., Vitrea crystallina) being permanently 

 " albino," while whole genera have become sinistral. The sinistral 

 mutations are perhaps of especial significance, inasmuch as in the 

 nature of the case they must arise " all at once." 



3. Forms, resulting from the immediate effect of the environment 

 upon the individual, and presumably not inheritable in the proper 

 sense of the word. I notice that Messrs. Pilsbry and Ferriss, in the 

 work already cited (p. 169) name a " form " of GoniobasisS These 

 variations might be held to have the least significance of the three, 

 but they are often striking, and are usually of interest from a 

 physiological if not from an evolutional standpoint. It must be 

 remembered, also, that while they are said to be immediately due to 

 the environment, this is only true in a partial sense ; there must 

 already exist the inheritable power of responding in this particular 

 way to the conditions found. This power of response, as exhibited 

 under diverse environments, is itself a thing of great interest to 

 every biologist, and no one can doubt its significance in relation to 

 the persistence and spread of species. 



The term " variety " may well be retained for use in cases which 

 cannot clearly be referred to one of the above categories. The 

 simple trinomial may be used for the subspecies ; in the case of the 

 others, " var.," " mut." or '' f." should be placed before the last 

 name. 



It should be added that not unfrequently " mutations " belong to 

 particular races, which are distinguishable only from their power of 

 producing them. Thus, I cannot see that the Cocfdicopa lubrica of 

 the Rocky Mountains and of England are in any wise different 

 shells ; but in England certain mutations are frequently produced, 

 which are never seen in the Rocky Mountains. 



1 Omitting, however, to name the very distinct mutations, figs. 27 and 28, 

 p. 167. According to the method I advocate, fig. 28 would be mut. spiralis, 

 and the same name would be applied to similar mutations of other species, 

 except when a different one had been earlier provided. 



