28 COCKERELL : THE GENERA LIMAX, ARION, AND HELIX. 



If the shells be classified according to number of bands only, 

 i.e., according to the presence or absence of one or more of bands 

 12345, then 32 varieties could be distinguished; if attention were 

 paid also to confluence of bands, 95 varieties ; if to resolution into 

 spots as well, 276 varieties. 



If the distinction into varieties proceed upon the variations in 

 either ground colour, lip colour, or number, confluence and spotting 

 of bands, then altogether there could be distinguished 35 times 276, 

 or 9,660 varieties of H. hortensis. The same reasoning applies to 

 the possible number of varieties of H. nemoralis. To distinguish 

 further varieties by the reduction of the bands to fine lines or trans- 

 parencies, &c, would increase the number by several thousands. 



Whether bandings in H. hortensis and H. nemoralis are per- 

 manent features or not, is a very pertinent enquiry ; but while there 

 is evidence to show that they are fluctuating, to constitute varieties 

 on their differences, is like distinguishing " men " by the colour of 

 their hair, or the freckles of their face. Men may be so distinguished 

 indeed, but is the distinction of scientific value? 



As a scheme of arrangement of shells in a cabinet, the schedule 

 will suit admirably ; but as yet it is too early to introduce it into our 

 text books as a scientific classification of varieties. That the system 

 of naming is not a satisfactory one, is evidenced by the fact that a 

 very similar proposal made by Mr. T. D. A. Cockerell,* in 1885, 

 was never generally adopted. The awkwardness of the names of 

 the several forms is forbidding, e.g., H. nemoralis, var. libellula, var. 

 albolabiata, var. hyalonzonata. 



Might I point out, that for identification, H. hortensis, var. 

 roseolabiata, should be made = var. hybrida, Jeff., by law of priority. 



THE GENERA LIMAX, ARION, AND HELIX. 



By T. D. A. COCKERELL, E.Z.S., F.E.S., 

 Institute of Jamaica. 



The facts mentioned by Dr. Scharff in his interesting and timely 

 note (Conch., p. 14, 1892) are undoubtedly of importance, but the 

 conclusion, as expressed in his work on the Slugs of Ireland (p. 513), 

 that Limax and its allies must be united with Helix in one family 

 seems to me unjustifiable, and I do not think any systematic 



Naturalist's World, vol. ii. p. 143 (18S5). 



