ipS C O N C H O L O G Y. 



cent. A large kind, flattifh, and like a 

 Cochlea Helix,, generally about two inches 

 in diameter, and jftrongly and thickly 

 wrinkled, with fharp prominent ridges like 

 plates, which are fpiked at regular diftances; 

 thcfe run acrofs the fpires ; but the whole 

 Shell is likevvife (lightly ftriated, accord- 

 ing to the run of them. This Trochus is 

 found in the Limeftone of Coalbrook- 

 dale in Shropfliire, and Dudley in Staf- 

 fordfhire. 



The iixteenth- family is the Cochleae, or 

 Snails ; the character of which is a round 

 mouth or approaching thereto, perfeflly 

 bordered, circumfcribcd, or defined, (ore 

 integro.) 



I (hall divide this family into five gene- 

 ra ; to wit, 



I. Nerits, (Nerita) or Snails with fe- 

 micircular mouths. (Semlkmaies.) PI. IIL 



2. Helices, 



