24r Remarks on Certain Species of 



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

 callosit}^ 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. dausa 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 If. dausa Say and S. 

 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. 



Pfeiifer, nevertheless, has H. dausa in the Synonymy of H. 

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

 as to Binney's of the latter. 



Tlie confusion has been increased by American Conchologists, 

 who have treated, in ray opinion erroneously, H. dausa Say 

 and H. Mitchelliana Lea as identical. It may also be remarked 

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

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

 adopted the views of Pfeiffer. 



Shuttleworth, in 1853, published (for private distribution only 

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

 them, of H. Pennsylvanica and S. 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. 



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

 same error with regard to H. dausa as Pfeifier. 



