Worth American Helicidce. 27 



HeSix claiisa l§ay. 



Synonymy. 



Helix clausa Say Jour, Acad. Phila. II. p, 154, 1821. 



" " Amer. Conch. No. 4, pi. 37, fig. 1, 1832. 



" Bimmj Bost. Jl. I. p. 482, pi. 15, 1837. 



" De Kaij N. Y. Moll. p. 31, ex parte, 1843. 



Pennsylvanica Pfr. Mon. I. No. 759, ex parte, 1848. 



" Chem. ed. 2, Helix No. 442, ex parte. 



MitchelUana *' " " " 332, t. 56, fig. 6-8. 



clausa Binney Terr. Moll. II. p. 107, ex parte, pi. 4, 1851. 



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 tlius described this species in the Journal of the Acade- 

 my:— 



"H. 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 a^io/a- 

 6m, but is much smaller, more rounded, and is subumbilicate. This 

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



I have already noticed that thia species has been confounded 

 by European authors with H. Pennsylvanica Green, and by 

 those of America with II. 3Iitchelliana Lea. 



H. clausa Say varies in form, 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 



Aira. Lto. Nat. Hist. Vol. VI. No. 10 et seq. SEPTEMBEE, 1858- 



