THE FROG'S TADPOLE 



igi 



frog finds it desirable to plunge into the water. He has 

 now grown a pair of air-holding sacs for breathing (the 

 lungs), opening from the gullet, whilst his gill-slits have 

 entirely closed up and ' disappeared. He moves quickly, 



Fig. 39. — ^The development of the frog's tadpole into a young frog. 

 I, Very young tadpoles (twice the natural size) adhering by theif 

 head suckers (comparable to those of the Ascidian, see Fig. 36) to 

 the leaves of a water plant; 2 and 2a, the-same enlarged to show 

 the external plume-like gills ; 3 and 4, later stages ; ,5, the hind ]egs 

 commencing to appear ; 6, with both fore and hind legs ; 7, the 

 tail is withering and disappearing; 8, the young frog. 



^nd with purpose; he catches small insects, little worms; 

 and such like food, and is a creature of altogefher'«iiperior 



