North American Helicidce. 361 



"With respect to the larger size of H. 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 H. major from II. albolabris. 



The differences in sculpture from certain localities are also 

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

 is a small, depressed, almost smooth variety of H. altemata, — 

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

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

 amples from Pennsylvania with well-defined, distinct ribs. 

 Some forms of H. ajpjpressa are without, while others have very 

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

 as to the absence or indistinctness of such striae 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 from Georgia and Tennessee, and in H. exoleta Binney 

 from Columbus, Ohio ; indeed it is shown in the figure of the 

 latter in Terr. Moll. pi. 10. I have noticed it moderately 

 developed in specimens of H. albolabris from Ohio and Mas- 

 sachusetts. 



I learn from Dr. Leidy that he has not examined the animal 

 of H. major. H. major and H. albolabris are in fact subject to 

 much variation in size, color, texture, sculpture, form of aper- 

 ture, and lip, and development of the latter, but there are no 

 constant characters in either to justify their separation as distinct 

 species. In my cabinet are specimens which I refer to H. 

 major, from Florida, Georgia, Tennessee, and South Carolina, 

 forms which seem to be intermediate from Alabama, Missouri, 

 and "Wisconsin, — and of II albolabris from most of the Eastern, 

 Middle, and "Western States, as well as from Virginia, North 

 Carolina, and Canada "West. 



