184 



entire in perfect shells; disk pierced with holes, disposed in a line parallel to 

 and near the left margin, the last commencing with a notch. 



PLICACEA.— Two Genera. 



Jlperture of the shell not effuse; columella plaited. 



Tornitella. Shell convolute, ovate cylindrical, mostly striated trans- 

 versely; no epidermis; aperture oblong, entire, the right lip sharp; one or 

 more plaits on the columella. 



T. flammea, T. fasciata, T. nitidula, T. pedipes. 



' solidula, ' auricula, 



Pyramidella. Shell turreted, no epidermis; aperture entire, demioval ; 

 outer lip sharp. Columella produced, subperforate at the base, and furnished 

 with three transverse plaits. 



P. terebellum, P. maculosa, P. corrugata, P. ventricosa. 



' dolabrata, ' plicata, 



SCALARIANA.— Three Genera. 



Shell without plaits on the columella; the margins of the aperture circular- 

 ly united. 



Vermetus. Shell thin, tubular, loosely spiral, adhering by the spire; 

 aperture orbicular, the margins united. An operculum. 



V. lumbricalis, V. maximus. 



Scalaria. Shell subturreted, ornamented with longitudinal, elevated, 

 interrupted, nearly acute ribs; aperture rounded, the margins circularly united, 

 and terminated by a thin, recurved varix. 



S. pretiosa, S. varicosa, S. raricosta, S. terebralis, 



' lamellosa, ' communis, ' Martinii, 3 fossil species. 



' coronata, ' australis, 



Delphinula. Shell subdiscoidal or conical, umbilicated, solid ; whorls, 



