The American Toad 



mouths are provided with horny jaws for scraping the tiny plants 

 from their supports and for biting off the deHcate ends of larger 

 plants.* The baby toad is not different from other babies in 

 being very hungry when it first comes into the world. He finds 

 the minute green plants just to his taste, and perhaps, too, the 

 microscopically-small animals that are in the ooze of the pond 

 bottom or in the slime at its top, or that cling to water weeds 

 between. 



At any time between the middle of June and the middle of 

 July, the shallow water of ponds will be found swarming with 

 toad tadpoles in every stage of development from the fully- 

 formed tadpole just described to the perfect little toad. (Figs. 37- 

 40.) They are exceedingly attractive little creatures. The 

 younger ones may change to toads within the twenty-four hours, 

 so rapid is the development. 



The whole length of the tadpole when it is from four to six 

 weeks old and is approaching the last stage of its development is 

 about one inch. The tail with its filmy fin constitutes three-fifths 

 of its entire extent. The soft skin is nearly black, but when we 

 look at it closely — especially with a lens — we can plainly see a 

 fine stippling of gold. The two nostrils are very prominent, 

 showing as small white openings. The eyes are small; the pupil 

 is round and black, and is surrounded by an iridescent iris. 



The tadpole now breathes by internal gills^ situated at the 

 sides of the throat. The water enters at the nostrils and at the 

 mouth — which is continually opening and shutting for the pur- 

 pose — passes through openings in the side walls of the throat, 

 thence over the gills, and out through an openir/g at the left side.' 

 This opening is shaped like a funnel with the small end outermost. 



When the tadpole begins to change into the toad, the first 

 sign which we can observe is the appearance of the hind legs. (Figs. 

 37-38.) These are mere rounded buds in the beginning and pro- 

 ject straight backward. Soon the division into toes can be seen, 

 and the joints are perfected. Then the leg is bent and the foot 

 projects outward. Now the tadpole begins using the legs, as well 

 as the tail, in swimming. 



In ten days or two weeks after the appearance of the hind legs, 



1 The tadpole of Buh americanus has the following mouth structure : The broad upper lip 

 has two rows of teeth; the broader lower lip has three rows of teeth; the border of the lower lip is 

 fringed with papillae and is doubled in at the comers of the mouth. 



'See Leopard Frog, pp. i8o; also Bullfrog, pp. 236. 



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