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



particulars they effentially differ from the 

 concamerated Shells, as the Nautili, &c. 

 Befides, thefe concamerations do not fecm 

 conftant to any particular ipecies, and ap- 

 pear rather the clofing up, and deferring 

 the old place of habitation of the fiih, 

 when it augments its Shell ; like as the 

 very bottom fpires of a turbinated Shell, 

 which the animal fills up as it grows big- 

 ger, and enlarges its habitations. The So- 

 len Arenarius of Rumphius, Tab. 41 . fig. E ; 

 and thofe of Davila, Tab. 21 ; which latter 

 author claffes them among his muitivalves, 

 are of this kind. 



The Vcrmiculi are frequently found in 

 the foifil ftate ; but I do not recoiled: 

 any fpecies, but what is known recent, 

 or from Sea, 



The laft and fourth family of fimplc 

 Shells, or not fpiral, is the Dentalia. The 

 definition of this family is, Simple tubuhir 

 Shells, of a regular, determinate, curved, 

 jponical fhape, and open at both ends. 



This 



