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 
