68 NATURE-STUDY REVIEW [12:2— Feb., 1916 



The color cells which enable the fish to make these quick changes 

 are in the inner skin and are under instant control. From a 

 beautiful blue with yellow tipped fins and large dark spots the fish 

 will fade to a cream white in a few seconds; any degree of color be- 

 tween these two extremes may be attained. The Grouper is also 

 able to poison its meat though it is considered a valuable food fish 

 and thousands of pounds are marketed yearly. They reach a 

 length of three feet and are among the most beautiful of southern 

 fish. The faculty of adaptive coloration occurs among many 

 kinds of animals, being most noticeable among the insects, but the 

 Grouper has no competitor under water. 



The Spiny Boxfish is unusual but not beautiful. The whole top 

 of the nearly flat back is covered with small horns or spikes of vary- 

 ing lengths; a square body, repulsive face and dull coloring do not 

 tend to give him attractiveness. The habitat is all along the 

 Atlantic seaboard. 



Occasionally the Boxfish tires of swimming and inflates its body 

 with air and floats upon the surface. They are of no food value 

 and seldom grow more than a few inches long. 



The Ladder fish, a native of the Amazon river, is beautifully 

 delicate with feelers and filmy fins ; the body is somewhat like the 

 sunfish though much more brilliant. Few aquariums have them, 

 they are difficult to keep. The two specimens in the New York 

 aquarium are watched carefully and the water kept at a fixed 

 temperature. In the tank there is a piece of large meshed wire 

 netting, to this the fish cling going slowly up and down, half swim- 

 ming and half climbing. 



