manual of the mollusca. 



[Family Yolutid^:] 



Contains Colttmbellina (p. 227), Mitba (Imbricaria, Cyh'ndra, 

 StrigatelJa, and Hyalina) (p. 231), V olut a (Volutilithes, Scaphella, 

 Volutomitra, and Melo) (p. 230), Cymba (p. 231), Mabginella 

 (p. 232), Yolvabia (p. 232), and 



Lybia, Gray, 1847. 



Synonyms, Harpella, Gray ; Enaeta, Gray. 



Types, L. deliciosa, Montf. ; L. harpa, Barnes. 



Shell ovate oblong, mitriform, thick, sometimes longitudi- 

 nally costated ; aperture subovate, with a large, number of 

 columellar plaits, the two anterior of these being the strongest ; 

 posterior portion of the inner lip provided with a large number 

 of short cross-plaits. Operculum ovate-elongate, thin ; corneous 

 nucleus at first nearly central, at a more advanced age sub- 

 apical. 



Distribution, 14 species. Pacific Ocean, America, Madagascar, 

 Australia, Japan, New Caledonia, Antilles. 



Fossil, 3 species. Cretaceous. India. The species in the 

 Tertiary strata have not been distinguished from Voluta. 



Cystiscus, Stimpson, 1865. 



Type, C. capensis, Cape of Good Hope. 



Shell resembling that of Marginella ; small, thin, ovate, 

 inflated, smooth, and polished ; aperture narrow, columella 

 plaited. 



Animal with an elongated foot, truncated in front ; head ob- 

 long, depressed ; tentacles triangular, flattened, and horizontal ; 

 eyes at the lateral margins of the head, at the bases of the ten- 

 tacles. Lingual dentition, 0*1 *0, resembling the rhachidian 

 teeth of Murex, thick and strong, with seven unequal conical 

 denticles. 



[Family Gyv-rmtdm] 



Includes Ebato, Cypbjea (Cyprovula, Luponia, and Trivia), 

 Ovula (Volva and Radius), Pachybathbon, Pediculabia, and 

 Dentioba, Pease, 1862. 



Type, D. rubida, Sandwich Islands. 



Shell differs from that of Pedicularia in the flat or excavated 

 columella, compressed, and toothed. 

 16 



