Till: FLOUNDER 



171 



Holothurians, etc. F. acus lives in Holothurians, and 

 another S| i r-fish. 



A; tlir head of the Ti — p7tali stand the flounders, hali- 

 but, an : . which are an extremelj modified type of the 

 order. In these fishes the body is very iiusymmetrical, the 

 fish virtually swimming en one side, tin' eyes being on 

 the upper side of the head. The upper side is 

 dark, due a.s m other fishes to pigment-cells; the lower 



, the pigment-cells being undeveloped. When 

 first hatched the body of the flounder is symmetrical, and m 

 form is somewhat cylindrical, like the young of other f 



Fig. 217.— Goose fish, one tenth natural i 



swimming vertically as they do, ami with pigment-celh 



the mi. ha- Bide <'f the body. The flounder is not born with 

 the eves on the same side of the head, hut ■ .du- 



ally passes from the blind t<> the colored side: the trai 

 of the eye from the blind side to the colored • curs 



very early in life, while all the faeial ! 3kull are 



Btill cartilaginous, long b they become hard and 



Bed, i.e., when the flounder (Plag - twenty-five milli- 



metres (one inch) long. Zoung flounders, when less than 

 two inches in length, are remarkably active compared 

 with the adults, darting rapidly through the water after 

 their food, which consists principally of larval surf 



