( 120 ) 



TABLE XX. 



Systematic Survey of the Phylogenetic Classification of 

 Vertebrates. 



I. Sftull4css (Acrania), or &ubc=IjcartEH (Leptocardia). 

 Vertebrates without a specialized head, skull, brain, or centralized heai-t. 



1. SiutlWfSS I. Tube-hearted ( , Lancelets 

 Acrania Leptocardia \ L Lancelets 



1. Amphioxida 



II. Animals fcutfj sftulls (Craniota) and with ccntraltjrti hearts (Pachycardia). 



Vertebrates with specialized head, with skull and brain, and with a 



centralized heart. 



