GENERAL CLASSIFICATION. 



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General Classification of Phylum Chordata. 



Class HYPOSTOMATA (extinct). 



Class CYCLOSTUMATA (Round Mouths), without true jaws. 

 My.vinc, hag-fish. Petromyzon, lamprey. 



SUB-PHYLUM CEPHALOCHORDA. Aniphi- 

 oxus or Lancelet. 



SUB-PHYLUM 

 UROCHORDA or 



TUNICATA. 



(sea- 



(Salpa type. 



I Ascidian type 



squirts). 

 Appendicularia (lar- 

 val type persistent). 



Surviving offshoots of ancestral Vertebrates. 



PHYLUM HEMICHORDA or ENTEROPNEUSTA (offshoots of incipient Vertebrates'?) 

 Balanoglossus, etc. ; probably Cephalodiscus ; possibly Rhabdopleura. 



Ancestry of Vertebrates. 



It is not at present possible to trace the path along which Vertebrates 

 have evolved, though our faith in the doctrine of evolution as a modal 



