MANUAL OF THE MOLLUSCA. 



Proserpixella, Bland, 1865. 



Etymology, diminutive of Proserpina. 

 Z^pe, P. Berendti, Bland. 

 Distribution, Mexico, 3000 to 4,000 feet. 

 Shell as in Proserpina; columella fold absent; aperture -with 

 one parietal larnelliforni plait. 



[Family Helicenti).ej 

 Contains : — 



Helicdta (Lucidella, Trochatella, Alcadia). 



Schasieheila. Shell with very close, long, spiral, epidermal 

 fringes. Distribution, 5 species. Central America and the 

 Bahamas. 



Perenna, Guppy, 1867 ; P. lamellosa, Chippy, Trinidad. Shell 

 like Helicina, depressed ; whorls Urate and carinate. Operculum 

 thin, suboval, concentrically striated; nucleus subcentral. 

 Animal like Helicina, Distribution, 2 species. Trinidad, 

 Yucatan. 



Bourciera, Pfeiffer, 1851. 



Type, B. helicina?formis, Pf. 



Shell like Helicina, dull, and without the columellar callosity : 

 columella toothed beneath ; aperture ovate ; peristome spread- 

 ing. Lingual dentition agrees with that of Helicina. Oper- 

 culum ovate, horny, few-whorled. 



Distribution, 2 species. South America. 



Stoastoma, and 



Geoeissa, Blanford, 1864. 



Type, Hydrocena pyxis, Benson. 



Animal furnished with hemispherical lobes in the place of 

 tentacles ; eyes normal ; foot short, rotund. Operculum semi- 

 oval, no spiral structure as in Helicina ; excentrically striated, 

 testaceous, transparent. 



Shell resembling that of Hydrocena, imperforated, small, 

 conical, amber-, or reddish- coloured, spirally sulcated or striated. 



Distribution, 6 species. Adhering to limestone rocks, India. 



[Famtty Acictltdje.] 



The genera enumerated in this family are : — AciCULA, Geo- 

 melaxla, Chtttya, and Truxcatella, the last with the follow- 

 ing 

 50 



