232 



The Colors of Fishes 



or ventral; a hidden spot of emerald in the mouth or in the 

 axil; an almost endless variety of sharply defined markings, 

 not directly protective, which serve as recognition-marks, if not 

 to the fish itself, certainly to the naturalist who studies it. 



These marks shade off into an equally great variety for which 

 we can devise no better name than "ornamentation." Some 

 fishes are simply covered with brilliant spots or bars or reticu- 

 lations, their nature and variety baffling description, while no 

 useful purpose seems to be served by them, unless we stretch 

 still more widely the convenient theory of recognition-marks. 



In many cases the markings change with age, certain bands, 

 stripes, or ocelli being characteristic of the young and gradu- 

 ally disappearing. In such cases the same marks will be found 

 permanent in some related species of less dift'erentiated colora- 

 tion. In such cases it is safe to regard them as ancestral. 



In case of markings on the fins and of elaborate ornamenta- 

 tion in general, it is best defined in the oldest and most vigorous 

 individuals, becoming intensified by degrees. The most bril- 

 liantl}' colored fishes are found about the coral reefs. Here 

 may be found species of which the groimd color is the most 

 intense blue, others are crimson, grass-green, lemon-yellow, 

 jet-black, and each with a great variety of contrasted mark- 

 ings. The frontispiece of this volume shows a series of such 

 fishes drawn from nature from specimens taken in pools of the 

 great coral reef of Apia in Samoa. These colors are not pro- 

 tective. The coral masses are mostly plain gray, and the fishes 

 which lie on the bottom are plain gray also. Nothing could 

 be more brihiant or varied than the hues of the free-swimming 

 fishes. What their cause or purpose may be, it is impossible to 

 say. It is certain that their intense activity and the ease with 

 which they can seek shelter in the coral masses enable them to , 

 defy their enemies. Nature seems to riot in bright colors where 

 her creatures are not destroyed by their presence. 



Intensity of Coloration. — In general, coloration is most in- 

 tense and varied in certain families of the tropical shores, and 

 especially about coral reefs. But in brilliancy of individual 

 markings some fresh-water fishes are scarcely less notable, 

 especially the darters (Etheostomiua) and sunfishes (Centra)- 

 cliida') of the streams of eastern North America. The brio-ht 



