162 NEW ZEALAND NATURE-STUDY BOOK 
it is able to breathe. Ina few days its mouth appears, the 
animal then begins to bite at the vegetation, and swims about 
by means of its long flexible tail. The external gills gradu- 
ally disappear, and a series of slits opens on the sides of 
Fig. 106.—Life stages of Frog—newly-hatched Tadpoles to the young: 
(a) eggs, 1) Tadpoles just hatched, (2) Tadpole with externa] gills, (Qa) fig. 2 
magnified, (3) side view of fig. 2, (4) Tadpole with internal gills, (5) Tadpole 
showing hind legs only, (6) Tadpole during the metamorphosis, (7) young 
Frog with tail only partially absorbed, (8) Adult. 
the head—these are the external gills. ‘The animal is now 
to all appearances a fish, obtaining a supply of oxygen 
through its gills, and being unable to live out of water. 
