318 ESSAY ON CLASSIFICATION. 



instead of recognizing at the outset these great plans, he 

 allows the external form to be the leading idea upon 

 which his primary divisions are founded, and thus he 

 divides the animal kingdom into three sub-kingdoms : the 

 first including his Artiozoaria, with a bilateral form ; 

 the second his Actinozoaria, with a radiated form; and 

 the third his Heterozoaria, with an irregular form (the 

 Sponges, Infusoria, and Corallines). The plan of struc- 

 ture is only introduced as a secondary consideration, upon 

 which he establishes four types among the Artiozoaria: 

 1st. The Osteozoaria, corresponding to Cuvier's Verte- 

 brata; 2nd. The Entomozoaria, corresponding to Cuvier's 

 Articulata ; 3rd. The Malentozoaria, which are a very 

 artificial group, suggested only by the necessity of esta- 

 blishing a transition between the Articulata and Mol- 

 lusca; 4th. The Malacozoaria, corresponding to Cuvier's 

 Mollusca. The second sub-kingdom, Actinozoaria, cor- 

 responds to Cuvier's Radiata, while the third sub-king- 

 dom, Heterozoaria, contains organized beings which for 

 the most part do not belong to the animal kingdom. 

 Such at least are his Spongiaria and Dendrolitharia, whilst 

 his Monadaria answer to the old class of Infusoria, about 

 which enough has already been said above. It is evident, 

 that what is correct in this general arrangement is bor- 

 rowed from Cuvier; but it is only justice to De Blainville 

 to say, that, in the limitation and arrangement of the 

 classes, he has introduced some valuable improvements. 

 Among Vertebrata, for instance, he has distinguished, for 

 the first time, the class of Amphibia from the true Rep- 

 tiles. He was also the first to remove the Intestinal 

 Worms from among the Radiata to the Articulata ; but 

 the establishment of a distinct type for the Cirripedia and 

 Chitons was a very mistaken conception. Notwithstand- 



