( 120 ) 



TABLE XX. 



Systematic Survey of the Phylogenetic Classification of 

 Vertebrates. 



I. .SfculWcss (Acrania), or &ubc=Ijc.artrtJ (Leptocardia). 

 Vertebrates without a specialized head, skull, brain, or centralized heart. 



1. SfutIl4c0S L Tube-hearted 

 Acrania Leptocardia 



1. Lancelets 



1. Atnplrioxida 



[I. Animals foitfj slutlls (Craniota) and with centralist! Ijrarts (Pachycardia). 



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



centralized heart. 



