S E G T I O N V. ifp 



Hight-handed Shells (heteroftropha) 

 4re fuch whofe whirls, or convolutions, 

 turn from right to \ei\^ or contrary to tlie 

 mofl general manner of turbinated Uni- 

 valves. 



Opercuhted Shells (cochlea operculatie) 

 are luch as have a loofe piece, Vv4iich fhuts 

 up or covers the apermre or mouth of the 

 Siiell, like a lid. So that the Shell really 

 confifts of two feparate and very unequal 

 pieces, viz. one piece flat and fmall, the 

 other large and fpiral : the former being 

 the lid, the latter the Shell itfelf. None 

 but turbinated Univalves hav^e opercula or 

 lids. 



Thefe opercula, or lids, fee PI. I. %, lo, 

 ane fmallj In comparifon to the Shells: and 

 of different fubftances, as (helly, leathery, or 

 horny. They are alfo of different forms, a^. 

 perfectly round, fimllunar, elliptical, oval, 

 or very lengthened: and they are generally 



I 4 wrought 



