REPTILES IN THE TARN AND THE GREEN LANES. 79 



strings, the former about March, about the roots of 

 plants, or rotting weeds, and this too in enormous 

 quantities. The geographical distribution of the 

 common frog is as remarkable as its exceeding 

 commonness. It is widely spread over Europe, from 

 north to south, except, perhaps, Ireland, where it 

 does not appear to have been naturalised until about 

 one hundred and fifty years ago. It is now more or 

 less common in that country a fact this, which 



Fig. 67. 



Spa*n of Frog. 



proves that Ireland is not unadapted to it, and 

 that the reason the frog does not occur there in- 

 digenously, is due to certain physical disturbances 

 which took place before it had been dispersed so far 

 to the west. The late Professor Edward Forbes 

 worked out the theory of the distribution of reptiles 

 in the British islands in a most remarkable manner. 

 As every one knows, they are not so abundant in 

 Ireland as they are in England, and popular tra- 



