51 Mollusca — Myzostomida 



Class Subcl Order 



Octopoda (Octobrachiata, Octopoida) cre-rec 



Vampyromorpha rec 



Belemnoida ^* (Phragmophora) mis-eoc 



SIPUNCULOIDEA 



SIPUNCULOIDEA REC 



Sipunculida REC 



ECHIU ROI DEA 



ECHIURIDA REC 



Echiuroina rec 



Xenopneusta rec 



Heteromyota rec 



SACCOSOMATIDA rec 



Saccosomatida rec 



MYZOSTOMIDA ^= 



MYZOSTOMIDA pal-rec 



Proboscidea rec 



Pharyngidea rec 



Arrangement preferred by paleontologists: 



Subclass Prionodesmacea (orders Paleoconcha, Taxodonta, Schizodonta, 



Isodonta, Dysodonta). 

 Subclass Anomalodesmacea (orders Septibranchia, Anomalobranchia). 

 Subclass Teleodesmacea (orders Pantodonta, Diogenodonta, Cyclodonta, 

 Teleodonta, Asthenodonta, Heterodonta, Pachyodonta, Desmodonta) 

 ®* Sometimes a subclass with orders Cryptodonta, Lipodonta, Palaeotaxodonta. 

 ^^ Includes: Pseudolamellibranchia. 



^° Includes: Schizodonta, Heterodonta, Adapedonta, Anomalodesmata, Sinu- 

 palliata, Integripalliata. 



^^ Sometimes ranked as a separate subclass with orders Mixochoanites, Schi- 

 stochoanites, Orthochoanites, Cyrtochoanites; or with orders Ellesmeroceroida, 

 Michelinoceroida, Ascoceroida, Oncoceroida, Endoceroida, Actinoceroida, Disco- 

 soroida, Nautilida; or with orders Bassleroceratida, Barrandeoceratida, Centro- 

 ceratida, Rutoceratida, Solenochilida, Tarphyceratida. 



^^ Sometimes ranked as a separate subclass with order Ammonitida; or with 

 orders Intrasiphonata, Extrasiphonata. 



^^ Includes: Teuthoidea, Sepioidea, Loliginacea, Architeuthacea. 

 ^* Sometimes used as subclass in place of Dibranchiata. 

 ^° Synonyms: Myzostomaria, Myzostoma. 



