Bufonidae 



the front ones suddenly appear, fully formed. The fact is they 

 have been growing for quite as long a time as the back legs have, 

 but were concealed under the membrane that covers the gills. 

 (See Fig. 280.) When ready for activity, the left one is extended 

 through the breathing-pore, and the right breaks directly through 

 the skin. We now have a strange-looking creature like a little 

 toad with a long tail. For, before the front legs appeared, changes 

 had begun in the region of mouth and eyes. The small mouth has 

 been replaced by a large one,^ the opening of which extends far 

 back under the eyes. The eyes have increased in size, and have 

 become elevated so that they look like the toad's eyes as we 

 know them in the adult. Now the tail seems mysteriously shorter. 

 It continues to become shorter (absorbed from within), until it is 

 a mere stub (Fig. 39), and finally disappears altogether. These 

 visible changes with the marvellous and radical transformations 

 that have taken place within, convert our black wiggling " polly- 

 wog " into a perfect toad. But so smooth and small! There is 

 no sign of a wart on his brown back and he is smaller than the 

 majority of our tiny tree-frogs at a corresponding stage of develop- 

 ment. 



For some time before the com- 

 pletion of the metamorphosis, 

 the tadpoles prefer to be wholly 

 or partially out of water. This 

 fact shows that lungs have quite 

 taken the place of the internal 

 gills, and that our little water 

 animals have been converted 

 into land animals. If confined 

 in deep water, tadpoles con- 

 stantly rush frantically to the 

 top to exchange a bubble of 

 foul air for one of fresh (Fig. 

 39 ), and they will finally drown 

 if not given opportunity to 

 stay above water. 



Just as soon as they lose 

 the tails, toads are likely to 



Late June — ^The little Toads leave the 



ponds when the Arrowhead begins 



to bloom 



1 See BullfroE, pp. 236 to 2»8. 



70 



