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



vifible ; and thefe charaflers fhould al- 

 ways be kept in view by the writers who 

 fet them forth. He divides all fhellsinto, 

 I. Simple Univalves, or thoie that are 

 not turbinated. 2. Turbinated Univalves, 

 by which he only underftands thofe whofe 

 whole form is fpiral, and not partly fo, 

 as is the Cyprea or Cowrie ; and, j. Bi- 

 valves. 



His firft Part, Simple Univalve Shells, 

 or not turbinated, contains clafs i. The 

 Limpets and Vermiculi. Clafs 2, The 

 Nautili, Nuces or Dippers, Cypreae or Cow- 

 ries, and Ammonia. 



Part II. Turbinated Univalves. Clafs i. 

 Of a lengthened aperture, or the mouth 

 open on the upper part ; as the Volutes, 

 Cylindars, &c. Clafs 2. Canaliculated, or 

 whofe aperture on the upper part ftretches 

 out into a long pipe or beak, as the Murices 

 Purpura?, Helmets, &c. Clafs 3. Whofe 

 aperture and tip are both lengthened, and 

 whofe firft, or body fpiie, is remarkably 

 6 fwelledj 



