84 FISHES. 



It is, besides, impossible to assign to the families of fishes the same 

 marked gradation that is visible among those of the Mammalia. Thus, 

 the Chondropterygians are connected with Serpents on the one hand by 

 the organs of the senses, and some of them even by those of generation ; 

 while the imperfection of the skeleton in others allies them to the Mol- 

 lusca and Worms. 



As to the Ordinary Fishes, if any one system is found more developed 

 in some than in others, it is not sufficiently pre-eminent, nor does it exer- 

 cise a sufficient influence over the whole to compel us to pay any regard 

 to it in a methodical arrangement. 



We will successively treat of these two series, commencing with the 

 most numerous, that of Ordinary Fishes, and placing at its head the order 

 richest in genera and species. 



ORDER I. 



ACANTHOPTERYGIANS. 



The Acanthopterygians form the first and by far the most numerous di- 

 vision of Ordinary Fishes. They are recognized by the spines which 

 occupy the place of the first rays of their dorsal, or which alone support 

 the first fin of the back, where there are two ; sometimes, instead of a 

 first dorsal, there are only a few free spines. The first rays of their anal 

 are also spines, and there is generally one to each ventral. 



The relations between the Acanthopterygii are so multiplied, and their 

 different natural families present so much variety in the apparent cha- 

 racters which we might suppose would indicate orders or other subdivi- 

 sions, that it has been found impossible to divide them otherwise than by 

 these same natural families, which we are compelled to leave together. 



FAMILY I. 



THE PERCH TRIBE.— PERCOIDES*. 



This family, thus called because its type is the Common Perch, com- 

 prehends fishes with oblong bodies, covered with scales that are gene- 



* In my first edition this family also comprehended the Bucca Loricatcv, the 

 Scieno'ides, and the Sparoiies. It was necessary to detach these three new familii s 



