IHE NAUTILUS. 



VOL. XXIX. JULY, 1915. No. 3 



VITREA CRIPTOMPHALA N. SP., WITH NOTES 

 ON THE INDENTATA GROUP. 



BY GEORGE H. CLAPP. 



VITREA CRYPTOMPHALA n. sp. Fig. 1. 



Shell thin, polished, very light horn-color to white, generally 

 white, translucent ; whorls 5 to 5, those of the spire regularly 

 increasing, the last widening very rapidly and doubling the di- 

 ameter of the shell. Aperture broadly lunate, sutures well 

 impressed, all whorls showing through the shell. Surface 

 sculptured with rather evenly spaced, radiating grooves contin- 

 ued to the base as in V. indentata and carolinensis, there being 

 from 23 to 34 on the body whorl. Micro-sculpture of even, 

 close, clear-cut spiral engraved lines like those of carolinenais, 

 best seen with a magnification of 25 diameters or over. Spire 

 much depressed, almost flat, the termination of the last whorl 

 slightly raised at the lip which is straight on the lower edge 

 and well curved forward above, projecting about 1 mm. beyond 

 the lower lip ; at the columellar end the lip is thickened and 

 joined to a tongue-like callus ivhich completely covers the umbilicus at 

 all stages of growth. There is a thin, microscopically granular 

 parietal callus, as in V. indentata. Base of shell well rounded 

 and less impressed in the umbilical region than indentata or 

 carolinensis. 



