148 BOOK OP THE BLACK BASS. 



Professor Richard Owen, in his admirable work, " 

 omy of the Vertebrates,' 7 Vol. I, says : 



" The varied, and often brilliant colors of fishes, are due 

 to pigment cells at different depths of the skin, but chiefly 

 in the active or differentiating area. Those of silvery or 

 golden luster are mostly on the surface of the scales. The 

 silvery pigment called ' argentine' is an article of com- 

 merce used for the coloring of fictitious pearls, and offers a 

 crystalline character under the microscope. The blue, 

 red, green, or other bright-colored pigment is usually asso- 

 ciated with fine oil, and occupies areolse favoring accumu- 

 lation at, or retreat from, the superficies, and thus effecting 

 changes in the color of the fish, harmonizing their exterior 

 with the hue of the bottom of their haunts." 



From the nature of the pigment cells, as portrayed in 

 this description, it is easy to imagine how susceptible 

 they are to the influences of such causes as those above 

 enumerated. 



The Salmonidce have been more studied, perhaps, than 

 any other family of fishes, and yet in none has there been 

 more confusion in classification, owing in a great measure 

 to the differences of external appearance, as caused by 

 these various influences. 



The eminent German naturalist, Seibold, says : " In 

 none of our native [German] fish is there such variety of 

 color, according to the different influences of food, water, 

 light and temperature, as in the toothed salmons." 



Another able German scientist, Carl Peyrer, says of the 

 common brook trout of Germany ( Trutta fario) : " The 

 color, and partly also the size which it reaches, vary ac- 

 cording to its location, the influences of light, the season, 

 water, and food, and therefore several varieties are dis- 



