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ANNUAL EEPOKT SMITHSONIAN INSTITUTION, 1908. 



The frog fishes in the Atlantic Ocean, at least, are mostly inhabit- 

 ants of the " Sargasso seas," or " Sargasso meadows," in mid-ocean, 

 and in the midst of the seaweed they find congenial homes. The 

 common form of the Atlantic, indeed, is generally called the " sargasso 

 fish " and is, according to J. Matthew Jones (1879), that " one species 

 of fish wdiich, above all others, seems to belong to the Sai'gassu'm,''' 

 and " which from its peculiar armlike pectorals is especially fitted to 

 rest upon the weed." Alexander Agassiz also (1888) declared that it 

 was " specially adapted to live among the floating algse." 



It is, as A. Agassiz has suggested and Mosely affirmed, like other 

 inhabitants of the Sargasso Sea, " in the same way colored weed-color 



d4 



Fig. 42. — A typical Ptcrophryne (Pteropliyrne ranina). After Jordan and Snyder. 



with white spots," and simulates the appearance of its environments. 

 Still further, there is that same subtle and even marvelous power or 

 rather susceptibility that is evinced by some other animals, of assimi- 

 lation to the A^arying hues of the plants amidst which it lurks. This 

 capacity of the fish for assimilation in color to its environments was 

 manifest in individuals observed by Dr. Hugh Smith. The animal, 

 in the midst of living vegetation, exhibits color harmonizing with it, 

 but when the seaweed has decayed to a brownish hue, its color also 

 changes to a corresponding shade. Conspicuous as the fish is when 

 isolated in the water, it has to be searched for when amidst its proper 

 environments. 



