310 MANUAL OP TH"E MOLLTJSCA 



Helicina, Lamarck. 



Tyjjc, H. Neritella, Lam. 



Synomjms, Oligyi'a, Say. Pacliytoma, Sw. Ampultina, BL 

 Pitonillus, Montfort. 



Shell globose, depressed or keeled, callous beneath ; aperture 

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

 expanded ; operculum shelly or membranous, squarish or semi- 

 ovate, lamellar. 



Animal Vik.Q CydoplLorus ; lingual teeth 3.1.3. (Gray.) 



Distribution, 162 species. "West Indies, Tropical America, 

 Pacific Islands, Australian Islands, Philippines. 



Suh-genera. Lucidella (aureola). Gray. Peristome more or 

 less toothed internally. 8 species. "West Indies, Tropical 

 America. 



TrocAa^eZZa (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 velyetj^ 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. Bistrihution, 17 species. Cuba, Jamaica, and Hayti. 



Stoastoma, C. B. Adams. 



Etymology, stoa, pillared, stoma, mouth. 



Type, S. x)isum. 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 

 have been added by the Hon. B. Chitty, who divides them 

 among several new genera. 



Family VII. — Aciculid^. 



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



^rimaZ with the muzzle rather jDroduced, slender and trun-' -j 

 cated ; eyes sessile on the upper j)art of the head, behind the ^ 

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

 behind. ,; 



AcicULA, Hartmann. 

 'lype, A. fusca, PI. XIL, Fig. 44. 



