23 G ESSAY ON CLASSIFICATION. 



luscoid Fishes, Entomoid Fishes, Carnal Fishes, and Sen- 

 sual Fishes, and so also in the classes of Keptiles, Birds, 

 and Mammalia. 1 



I have entered into so many details upon these vagaries 

 of the distinguished German philosopher, because these 

 views, however crude, have undoubtedly been suggested 

 by a feature of the animal kingdom which has thus far 

 been too little studied : I mean the analogies which exist 

 among animals, besides their true affinities, and which 

 cross and blend, under modifications of strictly homolo- 

 gical structures, other characters, which are only analogi- 

 cal. But, it seems to me that the subject of analogies is 

 too little known, the facts bearing upon this kind of 

 relationship being still too obscure to be taken as the 

 basis of such important groups in the animal kingdom as 

 the orders are; and I would insist upon considering the 

 complication or gradation of structure as the feature 

 which should regulate their limitation, if under order we 

 are to understand natural groups expressing the rank, the 

 relative standing, the superiority or inferiority of animals, 

 in their respective classes. Of course, groups thus cha- 

 racterized cannot be considered as mere modifications of 

 the classes, being founded upon a special category of 

 features. 



SECTION IV. 



FAMILIES. 



Nothing is more indefinite than the idea of form, as 

 applied by systematic writers, in characterizing animals. 

 Here it means a system of the most different figures 



1 See further developments upon geschichte, vol. iv, p. ,082. Compare 

 this subject in OKEN'S Naturphiloso- also the following chapter, 

 phie, and in his Allgeineiue Natur- 



