THE FISH 233 



tion. The position of the scales, overlapping in a backward di- 

 rection, is yet another adaptation which aids in passing through 

 the water. Its color, olive above and bright silver and gold below, 

 is protective. Can you see how ? 



The bream. A, dorsal fin ; B, caudal fin ; C, anal fin ; D, pelvic fin ; 



E, pectoral fin. 



The Appendages and their Uses. — The appendages of the fish 

 consist of paired and unpaired fins. The paired fins are four in 

 number, and are believed to correspond in position and structure 

 with the paired limbs of a man. Note the illustration above 

 and locate the paired pectoral and pelvic fins. (These are so called 

 because they are attached to the bones forming the pectoral and 

 pelvic girdles. (See page 268.) Find, by comparison with the 

 Figure, the dorsal, anal, and caudal fins. How many unpaired 

 fins are there? 



The flattened, muscular body of the fish, tapering toward the 

 caudal fin, is moved from side to side with an undulating motion 

 which results in the forward movement of the fish. This move- 

 ment is almost identical with that of an oar in sculling a boat. 

 Turning movements are brought about by use of the lateral fins 

 in much the same way as a boat is turned. We notice the dorsal 

 and other single fins are evidently useful in balancing and steer- 

 ing. 



The Senses. — The position of the eyes at the side of the head 

 is an evident advantage to the fish. Why? The eye is globular 



