North American Helicidw. 291 



renounces the above opinion, believes with me that H. Troos- 

 tiana Lea and H. plicata Say are distinct, and admits that the 

 Bishop's specimens are of the latter species. 



There is a good specimen of H. Troostiana Lea in the cabi- 

 net of the Academy, which was, I learn, received from Mr. 

 Sowerby. 



For examples of this species from Tennessee, I am indebted 

 to the late Judge Tappan, and to Mr. Postell of St. Simon's 

 Island, Ga. 



Helix Hazardi. 



Plate IX. Fig. 27-30. 



Synonymy. 



Polygyra plicata Say Jl. Acad. Nat. Sci. Phila. Vol. II. p. 161. 1821. 



Helix fatigiata Binn. Bost. Jl. III. p. 388 ex parte (excl. Syn. et pi. xix. 



fig. 3). 1840. 



Texasiana Pfr. Mon. Hel. I. p. 418 (excl. desc. et Syn.). 1848. 



Dorfeuilliana Desk, in Per. Hist. I. p. 7 3 (excl. desc. Syn. et 



fig-); 

 — — Texasiana Chem. ed. 2 Helix. I. p. 85 (excl. desc. Syn. et fig). 



fatigiata Binn. Terr. Moll. II. p. 193 ex parte (excl. pi. xxxix. 



fig. 2). 1851. 



plicata W. G. Binney Reprint of Say's Desc. of Terr. Shells of 



N. Amer. 1856. 



Polygyra Troostiana W. G. Binney Notes on Amer. Land Shells, 



Proc. Acad. Nat. Sci. Phila. p. 21. 1857. 



The following is Say's description with which his explana- 

 tory remarks, accompanying the description of H. fatigiata, 

 should be studied. 



" Polygyra plicata. — Shell convex beneath, depressed above, spire 

 slightly elevated ; whorls five, compressed, crossed by numerous raised, 

 equidistant lines, which form grooves between them ; aperture subreni- 



