Worth American HelicidcB. 25 



Desliayes, in Fer. Hist., describes 11. Mltchelliana, but refers 

 to the figure, which is rather of Pennsylvanica. 



The species under consideration may be readily distinguished 

 from clausa and Mitchelliana by its somewhat triangular aper- 

 ture, which is more like that of 11. elevata Say ; it is more ele- 

 vated, has usually 6 whorls, more convex, and with deeper 

 suture than in H. clausa. In mature shells the inner margin 

 of the peristome, near the columella, has a tooth-like callus, 

 very similar to that often prevailing in forms of H. zaleta Say, 

 thyroidxis Say, and alholahris Say. The umbilicus is invariably 

 more or less open in H. clausa, bat closed in II. Pennsylvanica 

 and Mitchelliana. 



This shell varies in size. The following are the dimensions 

 of the largest and smallest specimens in my Cabinet : 



Diam. maj. 19, min. 16|^, alt. 11, mill. 

 " " 16, " 14i, " 9, " 



The distribution of this species is far more limited than that 

 of II. clausa. I have seen specimens only from Pennsylvania, 

 Ohio, and Illinois ; but of clausa from Ohio. Kentucky, Ten- 

 nessee, Alabama, Illinois, Iowa, and Missouri. 



The mention of this and other species by De Kay in the New 

 York Fauna, because of the probability of their discovery in 

 that State, is calculated to mislead. 



Helix Eluotti Redfield. 



This species was described by Mr. John H. Redfield, in Annak 

 of Lyceum Vol. VI., p. 1*70. Figures are now giyen on PI. IX., 

 figs. 8-10. 



