DESCRIPTION. 157 



pearlaceous ; columella white ; grooves obsolete on 

 the under part ; umbilicus circular, perforate. 

 Inhabits 



Fig. 7. T. scalnrh. 



Shell conical, cancellate, or ribbed longitudi- 

 nally; whorls distant. 



D^Argenville Conch, tab. 11. fig. 5. 



Specimen white, umbilicate, imperforate; no 

 solid cohunella ; whorls round, connected by the 

 longitudinal, carinate, sub-oblique ribs, which are 

 not continuous, but encompass each whorl sepa- 

 rately, and adhere to each other at the upper and 

 lower part; extremely thin and brittle. 



Inhabits the coast of Barbarv. 



Fig. 8. T. Terehra. 



Shell tapering; whorls with acute carinate striae. 

 Lister Conch, tab. 590. fig. 4. 

 Specimeubrownishwhite; whorls rather convex. 

 Inhabits European, African, and Chinese shores. 



