172 ACANTHOPTERYGII. — LOPHIADiE. 



fishes, the law which assigns one sphere of action 

 to the Class, is much more uniform in its opera- 

 tion, admitting of scarcely any exception. 



This law is not, however, quite universal : there 

 are a few fishes which invade the domain of the 

 birds, as the proper Flying-fishes (Exoccetus), here- 

 after to be noticed, and some species {Dactylo- 

 pterus) in the Family of the Gurnards ; and in the 

 LophiadcB, the Family which we have now to de- 

 scribe, a still rarer aberration of habit is found 

 in fishes which are enabled to leave the water, 

 and crawl about on land, for hours, or even days 



together, thus emu- 

 lating the terrestrial 

 manners of quadru- 

 peds. 



To enable them to 

 do this, two peculiari- 

 ties of structure have 

 been conferred upon 

 them : the one modi- 

 fying the organs of mo- 

 tion, the other those 

 of respiration. The 

 pectoral and the ven- 

 tral fins in fishes cor- 

 respond with the limbs 

 of other vertebrate 

 BONES OF PECTORAL FIN OF animals, thc lormer 

 LOPHius. representing the arms, 



fore-legs or wings, the latter the hinder extremi- 

 ties. And this analogy, which is structural, 

 is not at all affected by the relative position 

 of these members, even though the ventrals 

 should be, as in the Family before us, situated 



