THE YELLOW PERCH 



317 



capable of appreciating sound vibrations. The ears also 

 serve as organs of equilibration, by aid of which the fish is 

 able to maintain its balance. The sense of touch is located 

 in the skin generally, and in the lateral-line organs. The 

 sense of taste is not greatly developed in the perch, and 

 the eyes are not adapted for vision at any great distance. 

 The organ of smell of fishes is peculiar 

 among vertebrates in that it has no con- 

 nection with the respiratory system. 



The Muscular System. The muscular sys- 

 tem consists principally of a 

 long, thick muscle on either 

 side, stretching from head to 

 tail. In the young fish this 

 muscle is divided into seg- 

 ments extending vertically 

 and corresponding in number 

 with the vertebrae. As the 

 young fish begins active ex- 

 istence the muscle segments 

 are bent and twisted, so that 

 for a portion of their extent 

 they seem to run zigzag. 



The Reproductive System. 

 Both the ovary of the female (Fig. 160) and the spermaries 

 of the male are of large size in the mature perch. They 

 open to the surface at the urinogenital opening. 



Development. Early in the spring the adult perch, which 

 have spent the winter in the deepest waters of ponds or 

 lakes, often without feeding very much, draw toward the 

 shore. The colors, especially on the males, begin to brighten, 

 till an adult perch in the full glory of his breeding colors is 

 one of the most beautiful objects in his domain. The time 

 of spawning varies with the climate : in the South it begins 



Fig. 161. Eggs of perch before and 

 after laying. (Reduced) 



From Bulletin United States Fish 

 Commission 



