91 



STROMBUS. 



A. Outer lip digitated, projecting in linear 



divisions or claws. (Plate XVII. Fig. 1.) 



B. Lobed. (Fig. 2.) 



C. Dilated. (Fig. 3.) 



D. Tapering, with a long spire. (Fig. 4.) 



Shell univalve, spiral, expanded. Aperture hav- 

 ing the lip usually dilated, and ending in a canal 

 inclined towards the left, or from the columella. 



A very remarkable peculiarity in this genus is 

 the sinus, or impression of the outer lip, which is 

 situated near the base, but is not at all connected 

 with the channel of the rostrum. This furnishes 

 a better discriminative mark than the direction of 

 the beak, which is often far from evident. It must 

 however be remarked, that several species, parti- 

 cularly in the last section, do not possess the se- 

 parate indentation, which are apparently Strombi 

 from the obliquity of the canal ; but as this con- 

 formation is not found in any but a Strombus, it is 

 a sure criterion of the genus, where it does exist. 



