THE FISHES lj 



fish, Amia, are some of the better known representatives 

 of this ancient group. 



The largest of the two divisions of the bony fishes, the 

 teleosts, includes the common fishes, such as cod, mackerel, 

 perch, bass, minnows, catfish, eels, etc. a vast and varied 

 assemblage occurring in fresh water and in the sea, at all 

 depths, and in all regions. They present almost every 

 conceivable modification of structure consistent with 

 remaining fishes, for what could be more diverse than the 



FIG. 135. Antennarius avalonis. (After Jordan.) 



puffy globe-fish, the grotesque sea-horse, the thread-like 

 pipe-fish, the large headed " angler," and the almost 

 impossible freaks of fish structure found in some of the 

 denizens of the deep sea? Even a superficial treatment of 

 these varied forms would require a whole volume and a 

 large one at that. 



The third sub-class of fishes, the Dipnoi or lung fishes, 

 are represented, like the ganoids, by only a few scattered 

 remnants of a once more numerous group. In these forms 

 the air bladder communicates with the ventral side of the 

 esophagus and functions as an organ for breathing air, 

 although these fishes also breathe by means of gills. The 



