North American Ilelicidoe. 61 



*' That this is not the same species increased in size by the influence 

 of a warmer climate, would seem to be proved by the fact that other 

 species are not larger in Florida than in situations further north, and 

 that //. trkientata Say, common in eveiy part of the country, is smaller 

 in Florida than elsewhere. The color of the respective animals is widely 

 different." 



Dr. Binney's illustration as to the influence of climate is an 

 nnfortunate one. In the Boston Journal he makes the same 

 remark, mentioning, however, H. fallax, instead of 11. triden- 

 tata, and with his notes on the latter (which he erroneously 

 treats as identical with the former), he figures (pi. 18, fig. 2) 

 as "the sm.all variety from Florida" of tridentata, a distinct 

 southern sj^ecics, which never attains a much larger size, viz. 

 the H. Hojyetonensis of Shuttleworth, who, in its synonymy, 

 refers to that same figure. 



With respect to the larger size of IT. major^ it may be ob- 

 served that species in this, as well as other countries, attain 

 extraordinary development in some particular district — if size 

 alone be considered, there is quite as much reason for separating 

 the II. tridentata and II. alternata of Ohio from the forms pre- 

 vailing in the Eastern States, as II. major from II. albolahris. 



The difi:erences in sculpture from certain localities are also 

 very striking. On Long Island, and near Albany, N. Y., there 

 is a small, depressed, almost smooth variety of II. alternata^ — 

 the Ohio form is striated, while the southern varieties are strongly 

 ribbed. The Ohio //. tridentata is almost smooth, — I have ex- 

 amples from Pennsylvania with well-defined, distinct ribs. 

 Some forms oi II. appressa are without, while others have very 

 numerous fine revolving striae. Dr. Binney is certainly in error 

 as to the absence or indistinctness of such stride in II major. 

 They exist in all the individuals of my extensive suite of speci- 

 mens, including the forms of which he gives figures. 



The tooth-like process on the margin of the lip near the um- 

 bilicus is by no means a good specific character ; it exists in II. 

 thyroidus fr<>m Georgia and Tennessee, and in H. exoleta Binney 



