276 THE STUDY OF ANIMAL LIFE CHAP. 



fish. There are sometimes pigment cells' in it, but these 

 are mainly or exclusively confined to the under-skin, 

 or dermis, both above and below the scales. 



6. Amphibians.- -The Amphibians of modern times are 

 neither numerous nor large. Giant Amphibians or 

 Labyrinthodonts were in evidence in the Carboniferous 

 period, but most of the modern frogs and toads, newts 

 and salamanders, are relatively pigmies. 



FIG. 88. THE GEMMEOUS DRAGONET (Callionymus Zyra), THE MALE 



ABOVE, THE FEMALE BENEATH. A TELEOSTEAN FlSH. 



(From Darwin.) 



Amphibians mark a momentous period in the evolution 

 of backboned animals, for they were the first to acquire 

 fingers and toes, genuine lungs, open communications 

 between the nostrils and the mouth, a three-chambered 

 heart, vocal cords, and a mobile muscular tongue. With 

 very few exceptions, young Amphibians breathe by gills, 

 and in some cases these gills persist in adult life. But 

 whether they do or not, the full-grown Amphibians have 



