tYRAMIDELLIDiE. 291 



Subgenus Ciirysallida, Cavponter, 1857. 



Shell small, pupiforrn, generoll}' cancellated; peristome con- 

 tinuous, edge of lip simple, columella profoundly but distinctly 

 plaited ; operculum (in the typical species) radiately corrugated. 

 West Goad of America, Japan, West Indies. P. communis, C. B, 

 Ad. 



This group might be equall}^ well placed in Odostomia. 



Section Mormula, A. Ad., 1863. 



Subulately turreted, rissoid, solid, thick, longitudinally plicate ; 

 aperture large, columella spirally tortuous, lip thickened witliin, 

 margin acute. P. Rissoina, P. aclis, A. Ad. 



Lancea, Pease, 1867, is a synonym. 



Section Styloptygma, A. Ad., 1860. 



Shell pupiform, subpellucid ; whorls a little convex, with 

 transverse grooves; aperture subquadrangular, lip dilated, colu- 

 mella obliquelj^ plicate above. P. stylina, A. Adams. 



Subgenus AcTiEOPYRAMis, Fischer, 1885. 



Shell elongate, imperforate, subconical ; whorls numerous, with 

 spiral striae, sometimes cancellated; aperture oval-elongated, 

 rounded in front ; columella with a strong spiral fold, P. striata. 

 Gray. 



The name is substituted for Monoptygma, Gray, 1840, preoc- 

 cupied by Lea, 1833. These shells recall the genus Actseon by 

 their form and sculpture, and may possibly include some of the 

 small groups 3Iyonia, Kleinella and Leucotina of A. Adams, now 

 arranged with that genus. 



Section Mumiola, A. Adams, 1863. 



Shell thin, elongate or ovate; whorls convex, cancellate or 

 granulose; aperture ovate, the lip-margin regularlj' arcuate. P. 

 spirata, a. Adams. Philippines. 



Section Careliopsts. Morch, 1874. 



Shell turriculated, having the form of Carelia Cumingii. P. 

 STYLiFORMis, Morch. West Indies. 



