of North American HelicidcB. 427 



Helix liirsMta Say. 



This species varies in size ; in my cabinet arc specimens 

 which measure as follows : 



V 



Diam. maj. 11|-, min. 10, Alt. Q^ mill. 

 " " g " 5 " 4 " 



The last whorl in front of the aperture, especially in the 

 larger forms, is more or less angnlated, bnt I have never seen 

 a specimen carinated. The position of the parietal tooth is 

 often rather oblique, but usually nearly parallel with the lower 

 lip, and is more or less distant from it. The nature of the epi- 

 dermis varies ; in some forms the hairs are very numerous, in 

 others comparatively few. Spiral impressed lines sometimes 

 occur beneath the epidermis, at the base of the shell. 



Helix stenotrema B?ea*wssac. 



Terr. Moll. pi. XLIL, fig. 4. 



^Y. G. Binney (Terr. Moll. lY., p. 61) treats this as distinct 

 from H. hwsuta, "its characteristics being constant in post- 

 pleiocene fossil as well as in recent individuals." He does not, 

 however, define the characters, and I confess that it is difficult 

 to do so satisfactorily. In H. stenotrema the notch is invariably 

 small, and more central than in II. hirsuta ; the parietal tooth 

 is more produced over the aperture, and its lower edge is a 

 regular curve, not somewhat sinuous as in the latter and //. 

 spinosa Lea ; it is also curved downwards at its outer extre- 

 mity, not terminating abruptly, as usual in those species. The 

 form of the parietal tooth, however, varies in II. hirsuta, from 

 which Ferussac's species can chiefly, if indeed not alone, be 

 distinguished by the size and position of the notch. 



H. stenotrema is not found in the Eastern and Middle States. 

 It does not vary much in size, seldom exceeding, 



Diam. maj. 10, min. 9, Alt. 6, mill. Tennessee, Shuttleworth ! 



