FISHES 



357 



Photograph by E. R. Sanborn, N. Y. Zoot. 6'oc. 

 FIG. 138. Common sunfish (Eupomotis gibbosus), one of the spiny-rayed fishes. 



tive members of the group, there are others 

 which lack the special characters for opposite 

 reasons : they are highly specialized members 

 of groups which once possessed them, and in 

 which they have been lost. Thus, for example, 

 the cycloid scales on the lower side of certain 

 flatfishes certainly represent a secondary adap- 

 tation, not a primitively cycloid character. 

 Certain families are entirely without scales. 

 The modifications in structure and appearance 

 are almost endless, producing many grotesque 

 forms. The flatfishes, adapted for life on Flatfishes 

 sandy sea bottoms, have one side colored and 

 the other, which is away from the light, color- 

 less. The head is curiously twisted and both of 

 the eyes are, of course, on the upper or colored 

 side of the fish. This metamorphosis, gained 

 through ages of evolution, is passed through in 

 the development of each individual fish. The 

 very young have the body symmetrical. 

 Reference 



JORDAN, D. S. A Guide to the Study of Fishes (Henry Holt & Co., 1905), is 

 the best work of reference. 



