310 MAinJAL OF THE M0LLT7SCA 



Helicina, Lamarck. 



Type, H. Neritella, liam. 



Synonyms, Oligyra, Say. Pachytoma, Sw. Ampultina, Bl. 

 Pitonillus, Montfort. 



ISliell globose, depressed or keeled, callous beneatli ; aperture 

 squarish, or semi-lunar ; columella flattened ; peristome simple, 

 expanded ; operculum shelly or membranous, squarish, or semi* 

 ovate, lamellar. 



Animal like Cyclophorus ; lingual teeth. 3.1.3. (Gray.) 



Distribution, 162 species. West Indies, Tropical America, 

 Pacific Islands, Australian Islands, Philippines. 



Sub-gen-era. Lucidella (aureola), Grray. Peristome more or 

 less toothed internally. 8 species. West Indies, Tropical 

 America. 



Trochatella (pulchella), Sw. Shell not callous beneath. ; peri- 

 stome simple, expanded. West Indies 20 species, Venezuela 1. 



Alcadia, Gray. A. Brownei, PI. XII., Fig. 43. Jamaica. 

 Shell helix-shaped, often velvety, callous beneath ; columella 

 flattened, straight; peristome slit in front; operculum shelly, 

 semi-ovate, with, a tooth-like process adapted to the slit in the 

 peristome. Distribution, 17 species. Cuba, Jamaica, and Hayti. 



Stoastoma, C. B. Adams. 



Etymology, stoa, pillared, stoma, mouth. 



Type, S. pisum, Ad. 



Shell minute, globose-conic or depressed, spirally striated; 

 aperture semi-oval ; peristome continuous ; inner margin 

 straight, forming a small spiral keel round the umbilicus; 

 operculum shelly, lamellar. 



Distribution, 19 species. Jamaica. S. succineum (Electrina, 

 Gray) has smooth whorls. I. Opara, Polynesia. 60 new species 

 bave been added by the Hon. E. Chitty, who divides them 

 among several new genera. 



Family YII. — Aciculid^. 



Shell elongated, cylindrical ; operculum thin, sub-spiral. 



Animal with the muzzle rather produced, slender and trun- 

 cated ; eyes sessile on the upper part of the head, behind the 

 base of the slender tentacles ; foot oblong, short, pointed 

 behind. 



AcicuLA, Hartmann. 

 O'ype, A. ftisca, PI. XII., Fig. 44. 



