126 



POPULAR CONCHOLOGY. 



side, which fits the plaits on the columella. — About 11 

 species ; also fossil. 



These pretty shells are found in the Indian, Australian, 

 and American seas. P. dolabrata, represented above, is 

 the best known species. 



Odontostoma. Flem. (Odostomia Flem. ; Jaminea 

 Brown?) — Shell ovate, turreted, conical, with the 

 apex rather obtuse ; aperture oval, the lips not 

 joined all round ; one tooth-like plait on the inner 

 lip ; operculum horny, rather spiral, transversely 

 striated. Animal resembling Turbonilla (Chem- 

 nitzia) in all its principal features (Forbes). — 

 Many species ; also fossil. 



Very small smooth shells ; found on the coasts of Britain 

 and the United States. Macgillavray found ten on the 

 coast of Scotland; and Forbes mentions that there are 

 between twenty and thirty on the British coasts. 



Monoptygma. Gray. — Shell turret-shaped, trans- 

 versely furrowed, the whorls even ; mouth egg-shaped, 

 with perpendicular columella. Animal unknown. 



The type of this genus is M. striata of Gray, from Java. 



Turbonilla. Risso. ( Chemnitzia D'Orb. ; Pyrgiscus 

 Phil. ; Parthenia Lowe ; Orthostelis Arad. et Mag.) 

 — Shell elongated, of many whorls, ribbed in the 

 direction of its length, often spirally striated, sur- 

 face not polished ; apex of the spire with a per- 

 sistent embryonic sinistral shell, forming the sum- 

 mit ; aperture oblong or subquadrate ; peristome 

 incomplete, thin but solid ; columella toothless, 

 rarely with a plication, straight or nearly so ; 

 operculum corneous, pyriform; marked by lines of 



