PERIOD OF CUVIER. 319 



ing some structural peculiarities, the Chitons are built 

 essentially upon the same plan as the Mollusks of the 

 class Gasteropoda, and the investigations made not long 

 after the publication of De Blaiiiville's system have left 

 no doubt that Cirripedia are genuine Crustacea. The 

 supposed transition between the Articulata and Mollusks, 

 which De Blainville attempted to establish with his type 

 of Malentozoaria, certainly does not exist in nature. 



If we apply to the classes of De Blainville the test 

 introduced in the preceding chapter, it will be obvious 

 that his Decapoda, Heteropoda, and Tetradecapoda par- 

 take more of the character of orders than of that of 

 classes, whilst among Mollusks, his class Cephalophora 

 certainly includes two classes, as he has himself acknow- 

 ledged in his later works. Among Eadiata his classes 

 Zoantharia, Polypiaria, and Zoophytaria partake again of 

 the character of orders and not of that of classes. One 

 great objection to the system of De Blainville is the use- 

 less introduction of so many new names for groups which 

 had already been correctly limited and well named by his 

 predecessors. He had, no doubt, a desirable object in 

 view in doing this, he wished to remove some incorrect 

 names ; but he extended his reform too far when he 

 undertook to change those also which did not suit his 

 system. 



CLASSIFICATION OF EHRENBERG. 



The characteristics of the following twenty-eight classes of animals, with 

 a twenty-ninth for Man alone, are given more fully in the Transactions of 

 the Academy of Berlin for 1836, in the paper q. a., p. 208. 



1st Cycle : NATIONS. Mankind, constituting one distinct class, is charac- 

 terized by the equable development of all systems of organs, 

 in contradistinction of the 



2nd Cycle: ANIMALS, which are considered as characterized by the promi- 

 nence of single systems. These are divided into : 



