North American Helicidos. 337 



Helix Pennsylvanica Reeve Conch. Ic. No. 676, ex parte, 1852 



clausa W. G. Binney Reprint of Say's Desc. p. 17, 1856. 



(non Ferussac.) 



Say thus described this species in the Journal of the Acade- 

 my:— 



"IT. Clausa, 



" Shell fragile, slightly perforated, subglobular, yellowish horn color, 

 above convex; whorls four or five ; aperture slightly contracted by the 

 lip ; lip reflected, flat, white, nearly covering the umbilicus. 



" Inhabits Illinois. Greatest breadth from one-half to three-fifths of 

 an inch. 



"A small but handsome species, which somewhat resembles albola- 

 bris, but is much smaller, more rounded, and is subumbilicate. This 

 shell also occurs, though perhaps rarely, in Pennsylvania." 



I have already noticed that this species has been confounded 

 by European authors with IT. Pennsylvanica Green, and by 

 those of America with H. Mitchelliana Lea. 



H. clausa Say varies in forrn, size, and sculpture. Speci- 

 mens in my cabinet from Selina, Ala., received from Mr. J. G. 

 Anthony, may be described as rather strong than fragile, not 

 shining or pellucid, the umbilicus only about half covered by 

 the reflected lip, depressed rather than subglobular ; the shell 

 as strongly striate above and below, as H. Pennsylvanica. 



I add the measurements of the largest and smallest indivi- 

 duals : 



Diam. maj. 18, min. 15, Alt. 10 mill. anfr. 6. 

 « u 12j « 10) « 7 « « 5. 



A specimen from Iowa is very similar to those from Alabama. 



From Wisconsin, Missouri, Illinois, and Kentucky, I have 

 forms which agree closely with Say's description, — in these the 

 reflected lip is less thickened, the aperture is more round, the 

 last whorl being more globose, — the umbilicus is more nearly 



