TAYLOR : ON THE VARIATION OF MOLLUSCA. 293 



system. I should be willing to accept for these combined or 

 complex varieties, compound names, joining the term distinguish- 

 ing the subsidiary character to that expressive of the more 

 important one, thus I would speak of LinmcEa peregj-a v. ovata- 

 alba and not of v. ovata s. v. alba. 



In bestowing names upon varieties which have not yet 

 received a name, I would advocate the adoption of conventional 

 terms expressive of the particular line of variation it is desired to 

 distinguish, thus such terms as globosa, curta, elongata, &c., 

 suggest themselves as suitable for varietal nomenclature. 



Dr. Jeffreys in dealing with the variations of Cochlicopa 

 hibrica, in his " British Conchology," has an instance of a colour 

 mutation existing both in the type and in the slender variety 

 lubricoides ; and to avoid confusing these two well-marked 

 forms, he applied to the same albine variation the distinct 

 names of viridula and hyalina, thus showing he appreciated 

 the undesirability of mixing together form-variations on account 

 of a subsidiary character possessed in common. 



Many conchologists seem to have a very incorrect notion 

 as to what a variety really is, and are disconcerted by the in- 

 sensible and gradual change from one form to another. They for- 

 get that these gradations of character fix the varietal status, and 

 that if the specimens showed distinct and constant differences, 

 it is probable that they would prove to be a different species. 

 Others while admitting the variability of species would not 

 bestow upon them definite names but would merely term them 

 varieties. To me this does not seem at all a satisfactory mode 

 of dealing with the difficulty, the mere fact of using the term 

 variety at all, implies that there is some difference worthy of 

 note, but if the method now spoken of be followed, we are left in 

 ignorance as to the special way in which the specimen alluded to 

 has deviated from the ordinary form, and in my opinion we might 

 with equal reason object to the grading of meteorological instru- 

 ments, because there are few if any distinct natural lines of 

 demarcation, as object to the naming of the more definite and, 



