22 ON THE ICHTHYOLOGICAL SYSTEM 



it is not to be inferred that they approach only in one 

 line and in one series. If the abdominal malacopterygians 

 may be ranged in this manner, and may commence even 

 with those who have some spinous rays, neither the apodal 

 nor sub-brachians should follow them. The gadi, for in- 

 stance, are as nearly allied as any abdominal fish, to certain 

 ac'anthopterygians, and there would be no reason to place 

 them after the abdominals, if the question were mooted 

 respecting the station they should hold in nature. If they 

 are mentioned after them, it is because the exposition of facts 

 in a book must necessarily be in a successive order. 



The same observation is applicable to the rest of the 

 fishes ; to those whose upper jaw is fixed, to those whose 

 branchiae are in tufts, and in particular to the great and im- 

 portant family of chondropterygians, which terminate the 

 class. It is chiefly in the last mentioned, that the futility 

 of classing animated beings in a single series is visible. 

 Several of its genera, the rays, and sharks, among others, are 

 considerably above common fish, by the complicated nature 

 of their organs of sense, and of the organs of generation ; 

 which are more developed in some parts than those even of 

 birds; yet other genera which are approximated by evident 

 transitions, such as lampreys and ammocoetes, become so 

 simplified, that they have been regarded as forming a pas- 

 sage to articulated worms ; for the ammocoetes certainly 

 possess not any skeleton, and their muscular apparatus is 

 attached solely to membranous and tendinous supports. 



Let it therefore never be supposed, that because one 

 genus, or one family, is placed before another, we consider 

 it more perfect, or superior to the others in the system 

 of beings. He alone could build up such a pretension, who 

 would attempt to place animal nature on a single line ; such 

 a project we have long since renounced, as one of the most 

 false that can be entertained in natural history. We should, 



