34 ECHINODERMATA-UROCHORDATA 



Order HOLASTEROmA 



Pourtalesia 

 Order SPATANGOroA (heart urchins) 



Spatangus; Echinocardium; Brissopsis 

 Class ASTEROroEA (starfishes) 



Order PHANEROZONA 



Astropecten; Porcellanaster; Luidia 

 Order SPINULOSA 



Asterina; Patiria; Anseropoda ( =Palmipes); 



Henricia; So/aster 

 Order FORCIPULATA 



Marthasterias ; Asterias; Leptasterias; 



Stichastrella; Pisaster; Brisinga 

 Class OPHIUROIDEA (brittle stars) 



Order OPHIURAE (serpent stars) 



Ophiura; Ophiothrix; Ophiocomina; Ophiopsila; 



Ophiactis; Ophiopholis; Acrocnida; Amphiura; 



Amphipholis 

 Order EURYALAE 



Aster onyx; Gorgonocephalus 



Phylum CHORDATA 



Sub-phylum HEMICHORDATA 



( = Stomochordata, Branchiotremata) 



Class ENTEROPNEUSTA (acorn worms) 



Protoglossus ( —Protobalamis); Saccoglossus 



{ = Dolichoglossus); Harrimania; Glossobalanus ; 



Balanoglossus ; Ptychodera; Schizocardium; 



Glandiceps 

 Class PTEROBRANCHIA 



Order RHABDOPLEURIDA 



Rhabdopleura 

 Order CEPHALODISCIDA 



Cephalodiscus : Atubaria 

 Class PLANCTOSPHAEROIDEAi 



Planctosphaera 



Sub-phylum UROCHORDATA (=Tunicata) 



Class ASCIDIACEA (sea squirts) 



Order ENTEROGONA 

 Sub-order Aplousobranchiata 



Clavelina; Polyclinum; Aplidium { — Amaroucium); 

 Didemnum 

 Sub-order Phlebobranchiata 



Ciona; Ascidia; Phallusia; Ascidiella; Perophora 



1 This class only contains a few larvae of unknown parentage. 



