PLATE 5 



EXPLANATION OF FIGURES 



Views of specimen no. 2: e, upon fine gravel (after two or three days); /, upon 

 dark, mixed sand (after two days). 



Views of specimen no. 3: o, after one day on present ground; h, taken on the 

 day when first placed on this sand. (Note the inferior power of adaptation shown 

 by this fish, as compared with the last. The harmony with the backgrounds in- 

 creased little if anv bevond the condition shown in the photographs). 



