THE BULLFROG loi 



absorbed,* while apertures on either side of the neck 

 close up, which were the external openings of the chamber 

 in which the secondary gills lie, and the young frog then 

 l)reathes by means of its lungs in the ordinary way. The 

 tadpole is extremely unlike the frog it is to grow into. Not 

 only does it breathe by gills in water, instead of by lungs 

 in air, but at first it has a very long tail, with which it 

 swims, and no limbs ; while when a frog, it has no tail 

 but long limbs, which are its only locomotive organs. 

 The tadpole has a very small mouth and very long 

 intestine, and feeds on vegetable substances. The frog 

 has a very large mouth and very short intestine, and 

 feeds only on animal matter. 



The common frog is distributed widely over the Old 

 World, though unknown to America, which, however, 

 possesses another species very like it. Similarly, the 

 bullfrog is unknown in the Old World, save in zoological 

 gardens, where it is always w^elcomed as a curiosity. 



The genus (Rana) to which these and other true frogs 

 belong has its headquarters in the East Indies and in 

 Africa, but extends over all the great regions of the 

 world except Australia and New Zealand. In South 

 America, however, there are but five species, while there 

 are no less than fifteen kinds in North America. 



The common toad {Jhffo vulgaris) is as widely dis- 

 tributed as is the common frog. Three species of the 

 genus Bufo are found in the northern parts of the 

 Old World, seven in North Ameiica, and seven in 

 Africa; twenty -two in the Indian region, and thirty- 

 six in tropical America, but none in Australia. They 

 all difiler from frogs in being toothless, while the frog 



* Thus, when Dickens makes one of his characters exclaim : 

 " What next ? as the tadpole said when his tail dropped off,'' he 

 was more amusing than accurate. 



