LAMARCK. 525 



2. Shell univalve \niilocular 



spiral sheathing the ani- 

 mal. 

 * Apertitre emarginate, or channelled at its hose. Gen. : 

 Conus, Cypr.'Pa, Ovula, TereLelluni, Oliva. An- 

 cillaria, Voluta, Mitra, Colunil)ella, Marginella, 

 Cancelhiria, Nassa, Piirpura, Ikiccinnni, Ehnrna, 

 Terebra, Dolium, Ilarpa, Cassis, Stronibus, Ptcro- 

 cera, Rostellaria, Murex, Fusus, Pyrnla, Fascio- 

 laria, Turbinella,Pleurotonia, Clavatula, Cerithiuni. 

 ** Aperture entire and tvitJwut a canal at its base. 

 Gren. : Trochus, Solarium, Tiu'bo, Monodonta, 

 Cyelostoma, Scalaria, Pupa, Turritella, lanthina. 

 Bulla, Bulimus, Agathina, Limna^a, Melania, Pyra- 

 midella, Auricula, Valvata, Ampullaria, Planorbis, 

 Helix, Helicina, Nerita, Natica, Testacella, Sto- 

 matia, Haliotis, Vermicularia, Siliquaria, Asj^ergil- 

 lum, Carinaria, Argonauta. 



/Gen. : Nautilus, Orbulites, 



3. Shell vuiivalve multilocu- Ammonites, Planulites, 



lar sheathing or enclo--^ Nummvilites, Spirula, Tur- 

 sing the animal. rulites, Baculites, Orthocera, 



vHippurites, Belemnites. 



II. Acephalous Mollusca. 



-,-r (Gen. : Ascidia, Biphores, 



^'^'^^^- iMammaria. 



CONCHIFEROUS. 



/Gen.: Pinna, Mytilus, Mo- 

 diola, Anodonta, Unio, Nu- 

 cula, Pectunculus, Area, 

 Cucullaea, Trigonia, Tridac- 

 na, Hippopus, Cardita, Iso- 

 cardia, Cardium, Crassatella, 

 Paphia, Lutraria, Mactra, 

 Petricola, Donax, Meretrix, 

 Venus, Venericardia, Cyclas, 

 Lucina, Tellina, Capsa, San- 

 guinolaria, Solen, Glycimc- 

 \ris, Mya, Pholas. 

 Shell inequi valve of t\vo| 

 or more valves, of which ' 

 the principal are un- 1 

 equal. 

 * Principal valve tuhular. Gen. : Teredo, Fistulana. 



Shell equi valve with or 

 without accessary j)ieces. 



