79 



C O N U S. 



A. Spire nearly truncate or flat. (Plate XIII. 

 fig. I.) 



B. Pyriform. (fig. 2.) 



C. Elongated, (fig. 3.) 



D. Ventricose, contracted at both ends. 



E. Thin, ventricose. (fig. 4.) 



Shell univalve, convolute and turbinate. — Aper- 

 ture effuse, longitudinal, linear, toothles?, entire at 

 the base. Columella smooth. Base attenuated, '' 

 often marked with oblique rugose striae. The aper- 

 ture is sometimes dilated. The whorls are mostly 

 flat, often channelled, rarely crowned. The supe- 

 rior beauty of this genus renders it highly interest- 

 ing, and the conical form distinguishes it from all 

 others, except the Voluta and Trochus, the former 

 of which has a plaited, and not a smooth colu- 

 mella; the latter a transverse, and not a longitu- 

 dinal aperture ; and tlie conoidal form is erect, and 

 not inverted. 



The shells of this genus are usually covered with 



