82 HELICEA. 



whorls plainly, the others rapidly retreating towards the 

 apex ; aperture very oblique, semicircular, removed from 

 the axis of the shell, bordered with a scarcely reflected, 

 white, heavy rim, grooved behind, and armed with two 

 stout teeth near the basal extremity, broadly reflected at 

 the junction with the body whorl ; on the parietal wall of 

 the aperture is a white fold, hardly connecting the extrem- 

 ities of the lip, and projecting across the aperture into an 

 acute point. 



Greater diameter 11, lesser 9, height 4 millimetres. 



Geographical Distribution. When describing this species 

 I had seen but one specimen of it in the collection of Mr. 

 Bland. It was supposed to inhabit Texas. Since that 

 time another specimen has been received by him from an 

 undoubted Texan locality. 



Remarks. The aperture of this curious shell resembles 

 that of H. fatigiata Say. It is readily distinguished from 

 that and all other described species by the umbilicus, 

 broad at the commencement, and rapidly narrowing be- 

 yond the second whorl, with the peculiar groove visible in 

 all the whorls of the umbilicus, of the same character as 

 that noticed by Say in auriculata, though deeper. 



The name is derived from the resemblance of the slightly 

 raised, rounded spire to a low dome. 



HELIX FATIGIATA SAY vol. ii. p. 193 (pars), pi. xxxix. fig. 4. 



Etlix fatigiala (Polygyra) SAY, (Binney's ed.) p. 37. 



BINNEY in Bost. Journ. 1. c. ex parte, (excl. syn. et fig.) 



SHUTTLEWORTH, Diag. n. Moll. ii. 



BLAND, N. Y. Lyceum, vi. 283; Notes, 7. 

 Helix Texasiana van B. CHEMNITZ, ed. 2. i. p. 86, excl. descr., syn. et fig. 



DESHAYES in Fer. i. p. 74, excl. desc., syn. et fig. 

 Helix Texasiana j3 PFEIFFER, Mon. Hel. Viv. i. 418; iii. 267. 

 Helix Dorfeuilliana DESHAYES in Fer. i. 73 (excl. syn.) pi. 69 D, fig. 3. 

 Eelicina fastiyiata DEKAY, N. Y. Moll. p. 82. 



The figure to which I have referred is a correct represen- 

 tation of the specimen of H. fatigiata deposited by Mr. 



