Binney on Terrestrial MoUusks. 191 



or more or less thickened, straight, expanded or widely 

 reflected. (PIV.) 



The only species of the old genus Cyclostoma found in 

 this country belongs to Cliondropoma, and not to Cyclos- 

 toma, as restricted by Pfeiff'er, as stated by Gould on p. 

 349. Other species are found in the West Indies. 



CHONDROPO.IIA DENTATUM Say.. vol. ii. p. 348, pi. Ixii. Ixxv. fig. 24. 



Cyclostoma dentatum S\y, (Bintiey's ed. ) p. 29. 



Chondvopoma dentatum Pfeiffer, Mon. Pncum. Viv. i. 286; ii. 140; Mtilak. Bl. 

 1856, p. 1-32. 

 Gray and Pfeiffer, Brit. Mus. Plian. 203. 



A view of the animal, twice its natural size, is given on 

 pi. 75, fig. 24. 



It will be noticed that I have omitted from the synony- 

 my the West Indian species C. lineolatwn, crenulatum, 

 Auberianum, and lumdatiim. It is at present impossible 

 to speak with certainty about their identity with dentatum. 

 Poey removes it from his Cuban Catalogue, (Mem. i. 893.) 



It is worthy of note that Orbigny describes Auberiartum 

 as having equal transverse and longitudinal striae. A 

 reference to the enlarged figure of the surface shows a 

 very different case in dentatum. 



Spurious Species. 



Cyclostoma Cincinnatensis Lea and DeKay, and C. lapidaria Say 



Linsley, and Kirtland, are species of Amnieola. 

 Cyclostoma marr/inalis Kirtland, (Ohio Rep.) and C. marginata 



Say, are species of Biilimus. 

 Cyclostoma tricarinata Say is a Valvata. 



FAMILY HELICINACEA. 



Operculum without any vestige of a spiral form, testa- 

 ceous, heavy or horny, thin, and furnishing no reliable 



