130 ANIMAL COLORATION. 



Ovulumuniplicatumisa shell-fish which lives upon the sea fan 

 (Leptogorgia tirgidatii). The latter has a stem of an orange 

 yellow colour, and is frequently found to exhibit swellings 

 caused by the presence of a barnacle which has been covered 

 over by the yellow tissue of the sea fan. Now, the Ondnnt. has 

 a yellow shell, and its soft mantle, which is protruded from the 

 shell during life, is of a darker orange. With another species 

 of Leptogorgia, of a deep rose colour mottled with white lines, 

 is found an Ovid um of a perfectly similar coloration. 



Another example of the same phenomenon is given by Prof. 

 J. Brown-Goode : " On certain ledges along the New England 

 coast are rocks covered with dense growths of scarlet and crim- 

 son seaweeds. The codfish, the cunner, the sea raven, the rock 

 eel, and the wry mouth, which inhabit these brilliant groves, 

 are all coloured to match their surroundings; the cod, which 

 has naturally the lightest colour, being most brilliant in its 

 scarlet hues, while others whose skins have a large and original 

 supply of black have deeper tints of dark red and brown." 



Mr. Brown-Goode suggests that the pigment is derived 

 directly from the red algae; directly in one sense, but indirectly 

 in another, for the fish in question are animal feeders; the 

 same reefs, however, swarm with crustaceans and other marine 

 organisms which are vegetable feeders, and whose stomachs, 

 therefore, are full of the algre and their pigment: it is from 

 these crustaceans that the fishes probably derive their colour; 

 just as, according to Dr. Giinther, the red flesh of the salmon 

 is coloured by a pigment derived from the Crustacea upon 

 which it feeds. There is, it is true, no positive proof offered 

 that this is really the case; no analysis of the pigment in 

 the fishes was made for the purpose of comparison with the 

 pigment of the alga?. But in the first place it is exceedingly 

 * Science, vol xv. (1890), p. 211. 



