COLOEATION OF THE BLACK BASS. 147 



young;, the colors are brighter and the markings more 

 distinct than in the adult fish, and it is my opinion that 

 the latter become entirely obsolete with age. 



The fins are likewise subject to variation in coloring 

 and markings ; they may be either dusky or greenish ; 

 reddish or yellowish ; and are, usually, more or less punc- 

 tulated or spotted. The tail is often lighter in color at 

 the base and outer edge, and dark or dusky between; thus 

 one of the names proposed by Rafinesque for the small- 

 mouthed species — CaUiurus punctulatus, i. e., "dotted 

 painted-tail " — was founded upon the peculiar coloration 

 of the tail of a young Bass, his description of the caudal 

 fin being : " base yellow, middle blackish, tip white." 

 Sometimes, however, especially in mature specimens, the 

 tail has a dark border, while the middle is of a lighter 

 tinge ; and often the entire caudal fin will have a uniform 

 coloration. 



There are commonly, several — usually three — dusky or 

 olivaceous streaks along the cheeks and gill-covers. 



Inconstancy of coloration is not exceptional with the 

 Black Bass, for all other genera of fresh water and ana- 

 dromous fishes exhibit this peculiarity in a greater or less 

 degree. Among the causes assigned for this phenomenal 

 feature, and which have been either proven true or made 

 tenable by actual experiment and careful observation, are : 

 (1) character of food ; (.2) condition, depth and tempera- 

 ture of water; (3) color and character of beds of streams, 

 lakes or ponds; (4) atmospheric conditions; (5) age; 

 (()) season of the year; and (7) the changes incident to 

 the breeding season ; while some assume that (8) the 

 power of changing color is voluntary with some, if not 

 all, fishes. 



