8 



FISHES OF THE VICINITY OF NEW YORK 



wardly projecting part being at first "cycloid" in shape and finally 

 developing a row of points or bristles on the free edge ("ctenoid" type). 

 The scales originally were faced with a thin shiny layer of "ganoine" 

 but most fishes have lost all traces of this layer and their scales have 

 become horny in texture. Sometimes the scales become reduced and 

 disappear or are replaced by bony plates, as in the Sturgeon. 



The reason for the marked difference between the body armor 

 (scales) and the bony plates on the head is that, with few exceptions, 

 the body must remain flexible for swimming, while the upper part of the 

 head must be rigid, like the bow of a ship. 



PIECE CONNECTING 

 3KULL AND UPPER JAW ,- 



SKULL ROOF, 



NOSE PIECE -. 



LOWER JAW 



GILL COVERS 



HINGE CONNECTING UPPER AND LOWER JAW 



Fig. 2. SKULL OF STRIPED BASS. 

 Drawing by F. A. Lucas 



The head of a fish (Fig. 2) is composed of very numerous and 

 complex parts which work together like the parts of an ingenious 

 mechanism. The head is first of all a structure for supporting and 

 protecting the highly sensitive organs, by means of which the animal 

 is guided toward its food. These sense organs, which represent our 

 nose, eyes, ears and organs of balance, are arranged in pairs on either 



