HELIX-PARTHENA. 71 



whorl ; spire short, apex obtuse, white ; sutures scarcely impressed 

 until the last whorl ; whorls 4, rapidly widening, the last either sub- 

 angulate or rounded in front of the aperture, always swollen and 

 rounded on its latter half, slightly descending anteriorly ; aperture 

 wide-lunar, oblique ; peristome reflexed all around, its upper and 

 outer margins arcuate, the baso-columellar margin somewhat 

 straightened, wide, flat, inner edge a little concave, not dentate. 

 Alt. 28, diam. maj. 40, min. 33 mill. 



Hayti. 



H. dominicensis PFR., Zeitschr.f. MaL, 1850, p. 71, and Conchy I. 

 Cab., t. 133, f. 14, 15. REEVE, Conch. Icon. f. 215 H. extensa 

 PFR., Monogr. i, p. 257 and Conchy 1. Cab. t. 120, f. 16, 17 (not H. 

 extensa Mull, nor Fer.) 



This form is never, even when carinated, so depressed and lens- 

 shaped as H. angustata, nor, on the other hand, is it ever so globose 

 as H. undulata. Its more prominent characters are the depressed 

 form, oblique malleation of the antepenultimate whorl, single periph- 

 eral brown fascia, and (usually) numerous bands denuded of the 

 cuticle. The peristome is well-reflexed, as in the H. angustata, and 

 is decidedly w r ider than in H. undulata etc. The typical form has 

 a rounded body- whorl. The form which Dr. Pfeiffer at first indenti- 

 fied as k< H. extensa " differs in being decidedlv carinated in front of 



O / 



the aperture. It is intermediate between H. angustata and the 

 present species. (PI. 17, fig. 45). 



H. DISSITA Deshayes. PL 6, fig. 60. 



Subglobose, depressed, smooth or striate, rugose, white, under a 

 brownish deciduous epidermis, encircled by distant narrow brown 

 lines ; spire short, obtuse ; whorls 4J, moderately convex, the last 

 thickened, convex, imperforate, extended at the aperture ; aperture 

 white, ovate-lunar, oblique, peristome thickened, reflexed, base 

 callous. Alt. 33, diam. 50 mill. (Desh). 



Hayti. 



H. dissita DESK., in Fer. et Desh., Hist, p. 248, t. 16, f. 1, 2. PFR., 

 Monogr. iii, p. 185 ; v, p. 284. 



This species was apparently known to Pfeifler only from the orig- 

 inal description, which I have translated above. I have identified 

 with it a suite of shells from San Domingo collected by GABB, which 

 may be described as follows: (pi. 17, figs. 46, 47.) 



Imperforate, depressed-globose, rather solid or thin, straw-colored, 



