87 



VOLUTA. 



A. Aperture entire. (Plate XV. fig. 1.) 



B. Subcylindrical, emarginate. (fig. 2.) 



C. Oval, effuse, emarginate. (fig. 3.) 



D. Fusiform, (fig. 4.) 



E. Ventricose, spire papillary at the tip. (fig. 5 .) 



Shell univalve^ convolute. Aperture not elon- 

 gated, subeffuse. Columella plaited^ without either 

 lip or umbilicus. 



Although this genus contain many apparently 

 incongruous shells, yet as it stands in the Linnaean 

 arrangement it is more easily discriminated than 

 almost any other, because all shells are referred to 

 it which possess the plaited columella, except a 

 few, which from evident and strong analogy are 

 to be attached to some other genus. The plaits 

 in the columella, which vary in number, but are 

 never very numerous, may be easily distinguished 

 from the teeth of a Cypraea; these last being uni- 

 formly placed on a thickened columellar lip, fiid 

 having corresponding dentations on the outer mar- 



