THE BULLFROG 115 



They are creatures which burrow beneath the soil 

 (which habit increases their resemblance to earthworms) 

 and feed on any small creatures they thus find, and also 

 upon mould. 



Non-scientific persons may perhaps ask, Why should 

 these worm-Uke, limbless creatures be grouped in the 

 class Batrachia with frogs and efts ? It is an extremely 

 natural question, but one which admits of a very easy 

 and satisfactory reply, although we cannot venture here 

 to inflict on our readers the strong dose of anatomy 

 which would be necessary to set out with any fulness 

 what that reply is. We may, however, call attention to 

 one character, as follows : No beast or bird or reptile 

 develops gills at any time of life, while all the batra- 

 chians do have them, and breathe by help of them at 

 first, with the exception of a few species, the conditions 

 of whose life render such aquatic breathing impossible 

 for them. There are, indeed, as we have seen, very 

 exceptional non-gilled forms, but these plainly and 

 evidently are the brothers of those other kinds which 

 do have gills, which form the overwhelming majority of 

 the whole class. 



The frogs and toads (Anoura), the efts ( Urodela), and 

 the worm-like kinds {Ophioniorpha), comprise all the 

 orders of existing batrachians. Another order, however, 

 is known to us, but to obtain evidence of that oi'der it 

 is necessary to dig very deeply into the geological 

 evidences of the past. 



When we begin our search into the geological records 

 of bygone ages, we do not find evidence of anything 

 startling or new in the tertiary or even in the upper 

 secondary rocks. Frogs and efts have indeed been found 

 in the tertiary strata, but they dilTer in no important 

 way from their representatives of our own time. 



