PYRAMIDELLA. 299 



Subgenus CRYPTOPLOCUS, Pictet and Campiche, 1854. 



Shell like Nerinaea, but without columellar or labral plaits ; 

 there is one plication on the posterior face of the aperture (as in 

 some Cerithiums) ; aperture rounded in front, without channel; 

 axis umbilicated or imperforate ; 7 species, Jurassic and Cre- 

 taceous. Europe. 

 N. MONILIFERA, d'Orb. 



Subgenus APTYXIS, Zittel, 1873. 



Shell turreted, nearly c}^lindrical, imperforate; whorls numer- 

 ous, not embracing; aperture lengthened subquadrangular, 

 without plications, the columella with a fold-like thickening. 



The synonyms are Pachystylus, Gemmellaro, 1878, and Aptyxi- 

 ella, Fischer, 1885. The latter name was given because of 

 Aptyxis, Troschel, 1868 which, however, is a synonym. 

 A. SEXCOSTATA, d'Orb. Jurassic. 



? Genus SOLENISCUS, Meek and Worthen, 1860. 



Shell fusiform, smooth, bodj'-whorl contracted below into a 

 distinct canal, columella with a single oblique plait. 

 S. TYPICUS, Meek. Carboniferous, Illinois. 



Genus PYRAMIDELLA, Lam., 1799. 



Typical Group. 

 P. VENTRICOSA, Guerin. PI. 72, figs. 63-65. 



Slightly striated longitudinally, the last whorl ventricose ; 

 yellowish white with irregular light chestnut undulating longi- 

 tudinal stripes, more or less intensified into revolving bands ; 

 columella triplicate. Length, 1-25 inches. 



Viti Islands, Vanikoro, Singapore. 



Besides the type, I figure a white variety. P. scitula, A. Ad. 

 (fig. 65), is only a younger state of this species. 



P. CINCTA, Reeve. PL 72, fig. 66. 



Smooth, white, with a broad central chestnut zone, appearing 

 on the spire whorls ; columella triplicate, perforation narrow. 



Length, 20 mill. 



/ Philippines. 



