220 



Monodouta articulate 

 ••••» lugubris 



Monodouta canaliculata 

 seminigra 



Monodonta lineata. 





TURBO. 



TURBO MARMORATUS. Linn. 



Mavoes Linn. pi. 28, Jiff. 1. 

 Chemnitz,5, tab. 179, fig. 1775, 1776. 



The species of this genus are very numerous and much 

 diversified, they differ from the Monodontae in never 

 having the columella truncated at the base, but having 

 it imperceptibly smoothed down on the right side; the 

 aperture consequently presents a round opening: in 

 many other respects they greatly resemble the preced- 

 ing genus. They have been blended together with 

 the Trochus by other authors, from which they are 

 very distinct, the whorls being constantly convex and 

 never flattened ; the shell is solid, resting almost entire- 

 ly on its aperture, and the columella is never visi- 

 ble. Shell subconical or turreted, whorls never com- 

 pressed, aperture entire, rounded, and closed by an 

 operculum; margin disunited at the upper part, col u- 



