PLATE 1 



EXPLANATION OF FIGURES 



1 Nassau grouper (Epinephelus striatus) in a dark banded phase beside gor- 

 gonians, of which the most conspicuous are the finely divided Gorgonia acerosa/" 

 and the fan-shaped G. flabellum whose color varies between dark brown and 

 blue. The bottom is gray and covered with coarse fragments of dead coral, 

 largely Acropora cervicornis. The fish's dark markings are brown, the ground 

 color, gray, more or less distinctly suffused with yellow. 



2 The same fish, as it appears upon leaving such surroundings. A colony of 

 Plexaura flexuosa is seen in the background, and two large sea urchins (Centre- 

 chinus setosum) in the upper left hand corner of the picture. Attention may 

 be called to the fact that this and the following figure show that the fish above is 

 fully exposed, in spite of all suggestion to the contrary. 



3 to 5 were tTaken in rapid succession, when upon another occasion the same 

 individual as above was led into the open by offering it food. 



3 This shows essentially the same phase as the preceding figure, though it is 

 perhaps a little lighter. 



4 The fish is now essentially gray, and its visibility could scarcely be dimin- 

 ished. The creature seems less substantial than its shadow, yet is in such per- 

 fect focus that in prints made directly from the negative the dark line of the 

 depression between its closed lips is perfectly apparent, as is also the pupil of its 

 eye. The bottom is clean white sand. There are several specimens of Iridic 

 bivittatus in the foreground. 



5 This records a change that occurred when the fish had approached the 

 dark bait closely. It became even more pronounced, but at present its meaning 

 is not positively determined (p. 551). 



6 Two hogfishes (Lachnolaimus maximus) over bare sandy bottom. They 

 are uniformly gray except for a dark spot at the base of the soft dorsal fin, and 

 a dark wash over the frontal and occipital regions. The large fish in the centre 

 of the picture is so definitely in focus that its individual fin rays may be 

 distinguished. 



7 A specimen of the same species photographed among brown gorgonians 

 (Flex aura homomalla). Its color is now dark reddish brown mottled irregularly 

 with light. Its fin spines also are visible. The change from the phase here 

 shown to that presented above, or vice versa, requires only an instant, and is sub- 

 ject to control by the experimenter. A specimen of Iridio bivittatus appears 

 just behind the larger fish. 



8 A branching cora' (Porites) growing upon a massive Orbicella head. The 

 picture, in which five specmens of Abudefduf saxatilis appear, was taken from the 

 bottom looking up on a line tangent to the head and making an angle of perhaps 

 30 with the horizontal. One or two fishes a little to the left of the middle show 

 the effect of blue-gray ground color in blotting out their contour, as it appears 

 against the watery background. Four or five dark stripes with alternating light ones 

 alone mark their position. Another near the face of the coral head and toward 

 the lower part of the picture faces the observer. Its stripes are little in evidence, 

 and from it one may get some idea of the way in which individuals vanish when 

 they wheel at right angles. 



Several small specimens of Haemulon sp. are also shown more or less distinctly. 



'"The names of the gorgonians are kindly supplied by Dr. L. R. Gary of 

 Princeton University. 



600. 



