69 



tion and combination and quite beyond the power of words 

 to describe. 



The entire absence of chromatophores results in albinism. 

 I have already called attention to the curious albino haddocks 

 occasionally taken on our coast. Sometimes these are of a light 

 golden color, and are in what Giinther calls a state of incipient 

 albtJiisni, the dark pigments having changed into yellow. This 

 has been observ^ed also in flounders, carps and eels, and in 

 the gold-fish, which in its native haunts in China is a dull 

 green ; the golden orfe and the golden ide have become per- 

 manent in a state of domestication. The silver-fish, a form 

 of gold-fish, is an example of still more complete albinism, 

 and a combination of the two conditions is very common in 

 the breeding ponds of the United States Fish Commission. 



The blind fish of Mammoth cave, Amblyopsis spclccus, is 

 an illustration of permanent adaptive albinism, and in the 

 abysses of the sea, where the light is very scanty, many fishes 

 appear to remain permanently in this condition. 



Adaptive coloration seems to be possible in quite another 

 way, through the secretion of pigment cells, which perma- 

 nently change the color of the fish to make it harmonize 

 with that of the bottom upon which it lives. On certain 

 ledges along the New England coast the rocks are covered 

 with dense growths of scarlet and crimson sea weeds. The 

 cod-fish, the cunner, the sea raven, the rock-eel and the 

 wry-mouth, which inhabit these brilliant groves, are all 

 colored to match their surroundings, the cod, which is natur- 

 ally lightest in color, being most brilliant in its scarlet hues, 

 while the others, whose skins have a larger original supply of 

 black, have deeper tints of dark red and ruddy brown. These 

 changes must be due to the secretion of a special supply of 

 red chromatophores. It has occurred to me that the material 

 for the pigmentary secretion is probably derived indirectly 

 from the algas, for, though the species referred to do not feed 

 upon these plants, they devour in immense quantities the in- 

 vertebrate animals inhabiting the same region, many of which 



