THE 



FIRST ORDE R 



OF 



F I S H. 



ACANTHOPTERYGII, 



Form the first and much the most numerous division 

 of common fish. They are known by the spines which 

 represent the first rays of the dorsal fin, or which alone 

 sustain their anterior fin of the back when they have 

 two. Sometimes instead of an anterior dorsal fin they 

 have nothing but a few free spines. Their anal fin 

 has also some spines instead of the first rays, and there 

 is in general one to each ventral fin. 



These fish have such numerous relations one with 

 another, their several natural families offer so many 

 varieties in the apparent characters which one might 

 think capable of indicating orders or other subdivi- 

 sions, that it is impossible to divide them otherwise 

 than by these natural families themselves, which we 

 are obliged to leave entire. 



