ADJUSTMENT OF FLATFISHES 431 



when viewed from a short distance. This seems especially remark- 

 able when we consider that the vividly contrasted black and white 

 condition of the fish was probably quite foreign to its experience 

 prior to captivity. 



15. Parallel aternating bands of black and white, each 1 

 centimeter in width. Upon these the fishes assumed an appear- 

 ance (figs. Im and 4/i) not very different from that displayed on the 

 1-centimeter squares, i. e. the dark and light areas were highly 

 contrasted. Nothing approaching a banded condition was mani- 

 fested, and this was hardly to be expected, considering the disposi- 

 tion of the permanent pigment areas of the animal. ^^ 



16. A white plate, bearing patches of dark>.sand, cemented in 

 place with Canada balsam. One fish (no. 11), after a sojourn 

 of fifteen days on white marble, was kept upon this spotted plate 

 for a period of eighteen days. A photograph, which was taken 

 after thirteen days (fig. 116) exhibits what would seem to be signif- 

 icant differences, in comparison with the appearance which had 

 been manifested upon the uniformly white bottom (fig. 11a). 

 I am not certain, however, that the somewhat speckled appear- 

 ance shown in the former figure did in reality result from the 

 character of the background; first, because these dark specks 

 were of inconstant occurrence, coming into view on occasions 

 and then disappearing again, and second because much the same 

 appearance could be produced by disturbing the fish, even when 

 the latter was on a clear white bottom. In favor of the influence 

 of the spotted plate, on the other hand, is the fact that another 

 specimen (no. 4) displayed a yet more conspicuously spotted sur- 

 face, in the presence of scattered flakes of asphalt varnish, which 

 had fallen upon the white bottom of the jar. The fish had previ- 

 ously been in the condition of extreme pallor, and devoid of promi- 

 nent markings. 



Upon these artificial patterns of black and white, the fishes 

 used (most of all no. 4) lost, in large degree, the brown and yellow 

 tints which they naturally possessed, and themselves became 



'' Of course such a banding, even if possible, would have been of cryptic value, 

 only if the fish lay in the same position relative to the bands, which, in fact, it did 

 not do. 



