78 REPTILIAN WATER TRESPASSERS. 



looking like little pink feathers attached to the sides of 

 the neck, the pink colour being due to the blood which 

 is seen through their delicate membranes. In this 

 state, the young animal is well-known under the name 

 of tadpole, and I very strongly advise my readers who 

 are within reach of a pond or ditch, to catch some tad- 

 poles and examine them with the magnify ing- glass. 

 Whether they be the young of Newt, Frog, or Toad, 

 does not in the least signify. 



In this form, they remain in the water for some 

 three weeks, during which time the limbs are begin- 

 ning to show themselves, and the lungs are being 

 gradually developed. Taking the Newt as our first 

 example, it retains through life the elongated and 

 fish-like shape of the body, and takes, in addition, 

 four legs, which are short, not very strong, but 

 quite capable of enabling their owner to walk upon 

 land. 



Another great and radical change is, however, taking 

 place. 



Not only does the animal gain limbs and lungs, but, 

 exactly in proportion to the development of the lungs, 

 the gills begin to become gradually less, until they 

 vanish entirely, and the whole of respiration is con- 

 ducted by means of the lungs. We have now a reptile 

 which is to its own order what the whales are to the 

 mammals. It lives in the water, finds its food below 

 the surface, and is, therefore, obliged to be able to 

 pass a considerable time without respiration. 



This object is achieved in a very simple manner. 

 In the case of the whales and dolphins, which are hot- 

 blooded mammals, so large an amount of oxygen is 



