287 



Upon a ftrifci examination of a great variety of both 

 thefe fpecies, we are aRoniflied they could ever have 

 been confounded. This fliell is invariably more rounded 

 at the top, more comprefTed or flattened, and the apex 

 more deprelTed ; and, what is remarkable, the apex is fo 

 thinly covered, that it is ufually worn, and the Columella 

 becomes pervious; fo that if a fmall pin is introduced at 

 the umbilicus the point may be felt at the apex. 



In the colour they are effentially, and invariably diffe- 

 rent; the flreaks of this are always broader, and of a much 

 finer colour; whereas the cinerarius is conftantly of a dull 

 cinereous, with the flreaks fo fine and regularly difpofed, 

 as to make the fliell appear longitudinally ftriated. 



Animal much like that of T. cinerarius, but darker and 

 more ftrongly marked with black annulations on the tenta- 

 cula, and lateral cirri: eyes pedunculated the fame, and 

 fituated behind or rather on the outfide of the tcntacula. 



10. 

 Trochus terreftris. Br. Zool. t. 80. f. lOS. Terrestris. 



Don. Br. Shells, iv. t. 111. 

 Chem. Conch, ix. t. 122, f. 1045. a. b. c. 

 Lijicr Conch, t. 61. f.SS. 

 Favan. t.64. 0. 1.3.— Turt. Lin, iv. p.471. 

 Pether Gaz. t. 22. f. 10. 

 Trochllus exiguus quatuor fpirarum elegantiffirae llriatus. Mor- 

 ton Northamp. p. 416. 

 Trochilus terreftris Mortoni Da Cojia. p. 36. ' 

 Trochus terreftris tertius. Id. p. 36. 



T. with 



