GENERAL CLASSIFICATION. 



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General Classification. 



CYCLOSTOMATA (Round Mouths), without true jaws. 

 Myxine, hag fish. Petromyzon, lamprey. 



CEPHALOCHORDA. Amphiuxus, or 

 Lancelet. 



UROCHORDA fSalpa type. 



Ascidian type (sea 



-] squirts). 

 TUNICATA. I Appendiciilaria (lar- 



^ val type persistent). 



Surviving offshoots of ancestral Vertebrates. 

 HEMICHORDA, or ENTEROPNEUSTA (offshoots of incipient Vertebrates?) 



Balanoglossus , &c. ; probably Cephalodiscus ; possibly Rhabdopleura. 

 Nemertean affinities (?) Chaetopod affinities (?) Arthropod affinities (?) 



