Classification. 7 



Classification. 



A tabic of the main divisions of the Mollusca according to the 

 system of classification -adopted in the arrangement of the 

 gallery is given below. The names of a few typical genera are 

 mentioned as examples under each of the orders. 



Phylum MOLLUSCA. 



Class I. AMPHINEURA. 



Order 1. Polyplacophora : Chiton. 



2. Aplacophora : Neomenia, Chaetoderma. 



Class II. GASTROPODA. 

 Sub-class I. Streptoneura. 



Order 1. Aspidobranchia : 



Patella (Limpet), Haliotis (Ormer), Turbo (Top- 

 shell). 



2. Pectinibranchia : 



Littorina (Periwinkle), Vivipara (River Snail), 

 Cypraea (Cowry), Buccinum (Whelk), Cari- 

 naria (Heteropoda). 



Sub-claSS II. EtTTHYNEURA. 



Order 3. Opisthobranchia : 



Bulla (Bubble-shell), Aplysia (Sea-Hare), Nudi- 

 branchia (Sea-Slugs), Clione (Pteropoda or 

 Sea- Butterflies). 



4. Pulmonata : 



Siphonaria (False Limpet), Limnaea (Water 

 Snail), Helix (True Snail). 



Class III. SCAPHOPODA. 



Dentalium (Tusk-shell). 



Class IV. LAMELLIBRANCHIA. 

 Order 1. Protobranchia : Nucula. 



2. Filibranchia : Mytilus (Mussel), Pecten (Scallop). 



3. Eulamellibranchia : Ostraea (Oyster), Gardium 



(Cockle), Teredo (Shipworm). 



4. Septibranchia : Cuspidaria. 



Class V. CEPHALOPODA. 



Order 1. Tetrabranchia : Nautilus, Ammonites. 



2. Dibranchia : Loligo (Squid), Sepia (Cuttlefish), 

 Polypus (Octopus), Belemnites. 



