1 86 DzveJIers of the Sea and Shore 



Their hues and markings almost invariably harmonize 

 with their native haunts, and a great many species are 

 capable of changing their colors momentarily to con- 

 form with the prevailing tints or tones of various locali- 

 ties. As nearly all of them are white along the under 

 surface of the body, it is not unlikely that to their ene- 

 mies which view them from below they would be con- 

 fused with the light above; and to the birds and other 

 enemies over them, their markings and coloration 

 doubtless make their forms quite indistinct. In the 

 perpetual darkness of the deep sea, camouflage is un- 

 necessary. As a consequence, we find the fishes there 

 unmarked, their entire bodies being an inky violet in 

 color, below as well as above. In truth, to say nothing 

 of the birds, such as slaty blue gulls and terns, which 

 are colored like the sea, there are throughout every 

 group of marine inhabitants — moUusks, crustaceans, 

 echinoderms, worms, etc. — abundant instances wherein 

 the perpetuation of the species is unquestionably due to 

 protective or aggressive resemblances. 



However, it is not my purpose to range the entire 

 ocean for specific instances or to recite even a rep- 

 resentative list of examples. Nor is it necessary. My 

 present object will be fully attained, I think, without 

 venturing beyond the comparatively narrow limits of 

 my tide pool. At any rate, let us see what it holds 

 for us. 



This briny basin is so situated that when the tide 

 is low its broadest expanse is separated from the waters 

 of the harbor by a reef of gravel and sand. Owing to 

 the shifting nature of this material, the outer shore of 

 the pool is continually changing by the tidal action; 



