320 TURBONILLID^:. 



suture well-impressed ; aperture subquadrangular, coluraella 

 straight, simple, lip subangular in front. E. TYPICA, A. Adams. 

 Corea. 



Subgenus MENESTHO, Moller, 1842. 



Shell turriculated, with spiral striae, or decussated ; aperture 

 oval. M. ALBULA, Fabr. Boreal Seas. 



PyramiS) of Couthouy, 1839 (non Schumacker, 1817), is a 

 synonym. 



Genus ODOSTOMIA, Fleming, 18^8. 



Shell small, perforate, oval, conoidal or turriculated ; colu- 

 mella with a feeble, oblique, more or less marked tooth ; aper- 

 ture oval or subrhomboidal, peristome not continuous. Oper- 

 culum horny, lamellar, subimbricated, with a median spiral 

 groove, inner margin indented. 



Animal elongated, the head large and robust, bearing two 

 conical tentacles, with e}'es at their bases, foot depressed, trun- 

 cated in front; mentum anteriorly bilobed. 



Very minute, usually smooth shells, having the habit of 

 Rissoa3, and, like them, sometimes found in brackish water. 

 The species are numerous, of universal distribution, from low- 

 water to 40 fathoms. Fossil, eocene. 0. PLICATA, Montagu. 

 Europe. 



The synonyms are Odontostoma, Turton, 1829; Odontostomid, 

 Jeffreys, 1837. 



The sections will only be used for the division of the Euro- 

 pean species on which they were founded ; those of other 

 localities will be described simply as Odostomia3. 



Section ODOSTOMIA, sensu stricto. 



Whorls smooth; lip not grooved wkhin, columellar tooth 

 well marked. 0. PLTCATA, Mont, 



BracJiystomia, Monts., 1884, is a synonym. 



Section MEGASTOMIA, Monts., 1884. 



Shell smooth ; aperture large, lip finely grooved within. 0. 

 CONSPICUA, Alder. 



Section ONDINA, Folin, 1870. 



Shell oval, thin; whorls smooth or spirally striated, colu- 

 mellar tooth obsolete. 0. OBLIQUA, Alder. 



