ON THE NATURAL ORDERS. 99 



festly impossible ; and yet, on the other hand, if only 

 one, however small, can be sufficiently analysed to 

 establish what has been advanced on natural arrange- 

 ment, philosophy teaches us to conclude that similar 

 results would attend the analysis of all others. No 

 other conclusion, in short, can be arrived at, whether 

 by inductive philosophy or common sense. 



CHAP. V. 



ON THE NATURAL ARRANGEMENT OF FISHES, THE PRIMARY TYPES 

 OF FORM, AND THE ANALOGIES THEY PRESENT TO OTHER 

 CLASSES OF ANIMALS. 



(85.) It is manifest to every naturalist, that the 

 most perfectly organised groups, in the great class before 

 us, are composed, as M. Cuvier has truly said, of the 

 osseous fishes, or those whose skeletons are of solid bone. 

 This being their most characteristic mark, it follows, 

 that although osseous fishes (less perfectly organised in 

 every other respect) may be found in other orders 

 which approach these, yet, that none with a carti- 

 laginous skeleton can naturally belong to this most 

 typical division. Now this great assemblage, like those 

 of all others equally typical in the animal kingdom, 

 resolves itself into two groups — the one composed of 

 such as have the rays of the dorsal fins more or less 

 spinous, the other of such as have them soft or articu- 

 lated. These groups were long ago perceived and 

 defined by the old ichthyologists ; and if any authority 

 were necessary to sanction our belief that they are truly 

 natural, we cannot cite a higher than Cuvier. The 

 osseous skeleton, however, although the paramount, is 

 not the only character possessed in common by these two 

 groups. The ventral fins, which are analogous to the 



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