PYRAMIDELLIDjE. 297 



Subgenus CHRYSALLIDA, Carpenter, 1857. 



Shell small, pupiform, generally cancellated; peristome con- 

 tinuous, edge of lip simple, columella profoundly but distinctly 

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

 West Coast of America, Japan, West Indies. P. COMMUNIS, C. B. 

 Ad. 



This group might be equally well placed in Odostomia. 



Section MORMULA, A. Ad., 1863. 



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

 aperture large, columella spirally tortuous, lip thickened within, 

 margin acute. P. RTSSOINA, P. ACLTS, A. Ad. 



Lancea, Pease, 1867, is a synonym. 



Section STYLOPTYGMA, A. Ad., 1860. 



Shell pupiform, subpellucid ; whorls a little convex, with 

 transverse grooves; aperture Bubquad rang alar, lip dilated, colu- 

 mella obliquely plicate above. P. STYLINA, A. Adams. 



Subgenus ACT^EOPYRAMIS, 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 Actaeon by 

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

 small groups Myonia, 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 regularly arcuate. P. 

 SPIRATA, A. Adams. Philippines. 



Section CARELTOPSIS. Morch, 1874. 



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

 STYLTFORMIS, Morch. West Indies. 



