COLOR CHANGES AND ADAPTATION IN FISHES. 1 97 



with a specimen adapted to this color. It is clearly darker and more reddish. No 

 indication whatever of black in the skin of the specimens in either the brown or the red 

 box, showing clearly that brown or red does not have the same effect as black or gray, 

 and that the color assumed on them is correlated with the length of the waves of light. 

 August 26, general color rich sepia brown, having slightly greenish tint. Scattered 

 all over the surface are small spots varying considerably in size and color; some are brown, 

 others greenish or pinkish, and still others brown with a greenish border or greenish with 

 a brown border. Considerable contrast between the color of the fish and that of the 

 background. Autochromed " and photographed. (Fig. 59, 72.) August 30, conspicu- 

 ously reddish brown with slight greenish tinge. My colleagues all remark about the 

 redness of this specimen and the striking contrast it shows when compared with speci- 

 mens of the same species adapted to other colors. 



Two other specimens were kept in the vermilion box with the one referred to above. 

 One of these was of the same species but much smaller (9 cm. long); the other (17 cm. 

 long) was P. dentatus. The color in both was very much like that described, but in 

 dentatus the markings in the skin were smaller and less conspicuous, and the color and 

 shade more uniform. 



Light bhie. — August 12, 3 p. m., P. albiguttus taken from the dark-blue box and 

 put into the light-blue box (Bradley's green blue, tint no. i). Half hour later much 

 lighter, grayish blue. August 27, simulation of the background excellent, finely mottled 

 grayish blue. Pattern remarkably uniform, no light or dark areas visible. (Fig. 73.) 

 A number of nemerteans which appear dark are seen in the fins. August 29, autochromed 

 and photographed. 



Dark hliic. — August 22, A. qitadrocellatta, 17 cm. long, caught in the seine and at 

 once put into the dark-blue box (considerably darker than Bradley's blue, shade no. 2). 

 This specimen changed rapidly to a dark bluish gray, except two large areas which 

 remained very light and somewhat iridescent. August 24, the fish is more bluish; the 

 light areas have a decidedly bluish tint; the tips of fins and tail are bright yellow. 

 August 26, somewhat darker and more bluish. Autochromed and photographed. 

 (Fig. 61, 74.) The colors as they appeared in the fish are fairly faithfully reproduced 

 in the autochrome. There is, however, probably a little too much of a greenish tint 

 in the light areas. This specimen was, at this time, transferred to the green box. 



Green. — August 26, A. quadrocellata, the same specimen as shown in figure 61, 

 taken from the dark -blue and put into the green box (Bradley's yellow green, shade 

 no. 2). After it was transferred it appeared quite as blue as before. The four ocelli 

 were distinctly blue. There was no indication of a greenish tint in any part of the 

 surface except the fins and the tail, which were somewhat translucent. August 30, 

 still distinctly bluish but has more of a greenish tint. The four ocelli are greenish 

 dark gray surrounded by greenish yellow rings about 1.5 mm. wide. The large light 

 areas have a pinkish cast. The tips of the fins and tail are bright yellow. In general, 

 the specimen is not nearly so intensely green as the P. albiguttus shown in figure 57, 

 which is still in the green box. Autochromed and photographed. (Fig. 62, 75.) 



Owing to the fact that it was necessary for me to leave Beaufort at this time, this 

 specimen was autochromed after it had been on the green less than four days, not nearly 



« Too much green in autochrome. 



