SIMPLIFIED LIST OF RECENT CLASSES AND ORDERS 

 Class Subcl Order 



Pteropoda butterfly-shells, pteropods 



Sacoglossa 



Acoela nudibranchs 

 Pulmonata land-snails, slugs 



Basommatophora boat-shells, ramshorns 



Stylommatophora slugs 

 BIVALVIA (Pelecypoda, Lamellibrcmchiata) bivalves, oysters, clams, 

 mussels, pelecypods 



Protobranchia 



Filibranchia 



Eulamellibranchia 



Septibranchia 

 SCAPHOPODA tooth-shells, tusk-shells 



Scaphopoda 

 CEPHALOPODA cephalopods 

 Tetrabranchiata 



Nautiloidea pearly-nautilus 

 Dibranchiata 



Decapoda squids, cuttle-fish 



Octopoda octopuses, argonauts 



Vampyromorpha 



SIPUNCULOIDEA 



[sipunculid worms] 



SIPUNCULOIDEA 



Sipunculida 



ECHI U ROI DEA 



ECHIURIDA 



Echiuroina 

 Xenopneusta 

 Heteromyota 

 SACCOSOMATIDA 



Saccosomatida 



M YZOSTOM I DA 



MYZOSTOMIDA 



Proboscidea 

 Pharyngidea 



ANNELIDA 



[segmented worms] annelids 



