TROCHUS TOP SHELL. 101 



jaws, and thence it is concluded that they feed 

 upon vegetables ; the shell has neither notch nor 

 canal, and the mollusk no proboscis. 



TROCHUS Perspective* 



STAIRCASE TROCHUS. 



Specific Character. Shell conical : umbilica- 

 ted ; the umbilicus large, funnel-shaped, the 

 whorls wind spirally round it and have a crena- 

 ted margin ; aperture nearly quadrangular ; shell 

 flat underneath, longitudinally and transversely 

 striated; colour greyish, beautifully variegated 

 with ochrous brown spots. 



This shell is the type of the modern genus So- 

 larium. It inhabits the shores of Asia, frequent 

 about Alexandria. 



TROCHUS Conckyliophorus. 



CARRIER TROCHUS. 



Specific Character. Shell conical, coarse, ob- 

 tusely plaited ; whorls imbricated,*)" base concave : 

 colour brownish white ; size an inch and a half 

 long, and an inch and three quarters broad. 



It is a singular fact in the natural history of 



* Plate IV. figure 5. 

 Imbricated, tiled, from the Latin imbrex, a tile. 



