300 North American Ilelicidm. 



closed, or masked ; aperture slightly contracted at the base, — a small 

 callosity on the inner margin of the other lip near its lower angle. Shell 

 rather more than half an inch in diameter. 



This shell somewhat resembles the H. clausa of Mr. Say, but may 

 very readily be distinguished from that species by the closed umbilicus, 

 the number of its whorls, and its general form. This shell is not uncom- 

 mon in the moist ground near Chartier's Creek, in "Washington Co., Pa. 

 I obtained five or six specimens with but very little trouble at that 

 locality, associated with the H. solitaria, profunda, and palliata. 



Authentic specimens are in the Cabinet of the Academy at 

 Philadelphia. 



This species has not been accurately determined by European 

 authors, who have confounded it with H. clausa Say and II. 

 Mitchelliana Lea, from which, however, it is entirely distinct. 

 Green's description, to be found only in a scarce work, has pro- 

 bably been unknown, but the shell was correctly described and 

 figured by Binney in the Boston Journal. 



PfeifFer, nevertheless, has II. clausa in the Synonymy of II. 

 Pennsylvaoiica, and refers to Say's figure of the former, as well 

 as to Binney's of the latter. 



The confusion has been increased by American Conchologists, 

 who have treated, in my opinion erroneously, II. clausa Say 

 and II. Mitclielliana Lea as identical. It may also be remarked 

 that Dr. Jay, in his Catalogue, 2d ed. (1836), admitted Pennsyl- 

 vanica and clausa to be distinct, but in the 4th ed. (1852) 

 adopted the views of Pfeifler. 



Shuttleworth, in 1853, published (for private distribution only 

 I believe), figures of many North American species, and among 

 them, of //. Pennsylvanica and II. Mitchelliana, but each 

 under the specific name of the other. He was evidently misled 

 as to the latter by Lea's description, and misapprehended the 

 former, not having seen that of Green. 



Reeves' figure fairly represents this species, but he has the 

 same error with regard to H. clausa as Pfeiffer. 



