300 THE NATURAL HISTORY 



plentiful and generally distributed, its spawn and 

 tadpoles swarming in spring in every pool of stagnant 

 water in the parish. The history of this animal in its 

 early stages of development is very curious and in- 

 teresting. It deposits its eggs in water, and at their 

 extrusion there is nothing strikingly remarkable about 

 them ; but in a very short time they increase so 

 enormously in size, that they form a mass a great 

 many times larger than the animal that laid them. 

 In a few weeks the little black tadpoles are liberated, 

 and at this stage of their existence they are each 

 provided with little tufts of fine thread-like processes 

 on each side of the head, these appendages are ex- 

 ternal gills, which enable them to breathe in the water 

 like fishes. In their further development, these ex- 

 ternal gills first become internal ; and subsequently 

 are replaced by true air-breathing lungs appropriate 

 to the change of habits of the young frog, when it has 

 become a terrestrial animal. Its mechanical functions 

 of inspiration, however, are due to th%pressure of the 

 tongue against the integuments under the lower jaw, 

 while the mouth is closed, and strange as it may 

 appear, a frog would as inevitably die of suffocation if 

 the jaws were permanently propped open, as the 

 respected reader of this would, if both mouth and 

 nostrils were hermetically sealed up.* 



The well known Common Toad (Bufo vulgaris) 

 differs little from the frog in the history of its re- 

 production. The spawn of both is frequently found in 

 the same pools together ; and the distinction between 

 them is that the toad's is deposited in long double 

 chains, while that of the frog is in irregular masses; we 

 know of no striking difference between their respective 

 tadpoles. Much has been said and written on the 

 alleged venomous character of the toad, some natural- 

 ists assuring us that it is a most dangerous reptile ; 



* Encyclopaedia of Natural History, article " Batrachia." 



