A FISH FROM A PELAGIC EGG. 



31 



and there is nothing specially wonderful in this, when the 

 conditions in the endoderm of Hydra, and other instances of 

 intracellular digestion are considered. 



It has been mentioned that these minute and delicate 

 little fishes are nearly transparent, and this is more or less 

 the case throughout, though in the majority — even before they 

 leave the egg — points of pigment ap- 

 pear here and there in the skin, so as 

 to give them a distinctive character 

 (Fig. 2). After hatching, these pigment- 

 spots branch out in a stellate manner, 

 thus becoming more evident, and it is 

 found that in most cases each little 

 food-fish has colours of its own. Thus 

 the cod (Fig. 3) is known by its four 

 somewhat regular black bands, the pig- 

 ment on the haddock being less defined, 

 and chiefly aggregated behind the head, 



the whiting by its canary-yellowish hue, the gurnard by its 

 chrome-yellow, the ling by its gamboge-yellow, the flounder 

 by its yellow and black, the turbot by its ruby-red, the sole 

 by its stone-colour and so on. All these hues, however, become 

 greatly modified during subsequent development, indeed the 

 pigment in no group of vertebrates shows more remarkable 

 changes between the young and adult states than certain of 

 our food-fishes. Thus, for instance, the cod is characteristically 



Fig. 2. Flounder, show- 

 ing pigment in the 



,^^ 



Pio. 3. Larval Cod with black spots 

 or bands, slightly enlarged. 



FiQ. 4. Aggregation of pig- 

 ment in Post-larval Cod. 



speckled in its tiny youth (Fig. 3), next it becomes more or 

 less uniformly tinted, then the pigment groups itself somewhat 

 irregularly on the sides (Fig. 4) ; thereafter it is boldly tes- 

 sellated (Fig. 5), subsequently blotched with reddish brown, 

 and finally in its adult condition it again puts on more or 



