( 120 ) 



TABLE XX. 



Systematic Survey of the Phyfogenetic Classification of 

 Vertebrates. 



I. Shull=Ics0 (Acrania), or 8Tubr=f) cart ell (Leptocardia). 

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



1. Amphioxida 



[I. Animals fcritf) skulls (Craniota) and with ccntraltjcti Ijrarts (Fachycardia), 



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



centralized heart. 



Amniota 



