ZOOLOGICAL CLASSIFICATION. 



2. Deuterostomata. 

 . Schizoccela. b. Enterocoela. 



Enteropneusta, 



Annelida Gephyrea (?). Brachiopoda. 



polychceta. Polyzoa (?). 



Arthropoda. Mollusca. Echinodermata. 



c. Epicoela. 



Tunicata (or Ascidioida}. 

 Vertebrata. 

 B. AGASTRE^E (provisionally). 



Cestoidea. Acanthocephala" 



Journ. Linn. Soc., Zool. xii. p. 226. 



Some alterations in this scheme have since been made ; Spongida 

 have been added to the type of the Coelenterata, and the Agastreae 

 are relegated, the Cestoidea to Trematoda and Acanthocephala 

 to the Nematoidea. The italicized groups or series are natural 

 divisions to the extent and limits of which most biologists are 

 agreed. 



As the Animal Kingdom can no longer be compared to a 

 " chain extending from the monad up to man," a natural linear 

 arrangement is impossible. From the Protozoa the Coslenterata 

 branch off on one side and Vermes on the other ; from Vermes 

 proceed (1) the Echinodermata, (2) the Mollusca, and (3) the 

 Arthropoda ; and from the Mollusca follow, apparently after a 

 long interval, the Vertebrata. The annexed scheme will show at 

 once their relative position : 



Vertebrata. 



Echinodermata. / 



^\ Mollusca. 

 \ 



Arthropoda. 



Coelenterata. 



Vermes. 



Protozoa. 



