North American IIelicid.ce. 301 



Deshayes, in Fer. Hist., describes II. Mitchelliana, 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 II. 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 II. zaleta Say, 

 thyroidits Say, and albolabris Say. The umbilicus is invariably 

 more or less open in II. clausa, but closed in H. 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, " 14^, " 9, " 



The distribution of this species is far more limited than that 

 of H. 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 Elliotti Redfield. 



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

 of Lyceum Vol. VI., p. 170. Figures are now given on PI. IX., 

 fiss. 8-10. 



