HOW THE MAMMALS DEVELOPED 199 



laid and quickened no other attention is paid to them 

 by either of the parents. 



Fish are stupid almost beyond the comprehension 

 of those who are not students of the minds of ani- 

 mals. Frogs and toads are a distinct step in advance, 

 and hence their mental activities play a larger part in 

 the process. 



In the love-making of the frogs and toads the song 

 has an important share. In each species the voice is 

 a little different from that of any other. In our 

 familiar garden toad we have an excellent illustra- 

 tion of the method common to the entire group. 

 When spring comes an impulse seems to stir in all 

 the toads of a neighborhood. Heretofore they have 

 stuck faithfully to dry ground ; now they start off for 

 the water. Whether their impulse is simply to move 

 down hill or whether they by some means detect the 

 near presence of water, I cannot say. Certainly a 

 new fountain on a lawn will secure in spring its 

 prompt and full share of the neighborhood's toads. 

 In any event the toads of a district congregate in 

 great numbers in any pond or along the edge of any 

 moderate stream. Within a short time their flutelike, 

 quivering voice is heard far and wide. That this note 

 has an attractive power over the female there is no 

 doubt. She herself makes no effort to imitate, but 

 the song of her mate is persistent and exceedingly 



