DESCRIPTION. ]69 



Specimen white, umbilicate, imperforate ; no 

 solid columella ; 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 Barbary. 



Fig. 8. T. terehra. 



Shell tapering ; whorls with acute carinate striae* 



Lister Conch, tab. 590. fig. 4. 



Specimen brownish white; whorls rather convex. 



Inhabits European, African, and Chinese shores. 



PLATE XX. 



Fig. 1. Helix Scarabceus. 



Shell ovate, two-edged, sub-umbilicate ; aper- 

 ture toothed. 



Lis I er Conch, tab. 577. fig. 31. 



Specimen brown variegated with pale spots, 

 outer lip and teeth horny, white; whorls contiguous, 

 double convex; aperture narrow, compressed, flex- 

 uous ; each lip with three teeth. 



