438 ANIMAL LIFE-HISTORIES 



Diving again, after a moment's time, the frog brought up a second 

 mass of mud near the first. This was repeated many times, the 

 result being the gradual erection of a circular wall. From time to 

 time the builder's head and front part of body appeared suddenly 

 with a load of mud on some opposite point. But what astonished 

 us in the highest degree was the manner in which it used its 

 hands for smoothing the inside of the mud wall, as would a mason 

 with his trowel. When the height of the wall reached about four 



Fig. 962. Nests of the Ferreiro (Hyla faber) 



inches the frog was obliged to get out of the water. The parapet 

 of the wall receives the same careful smoothing, but the outside is 

 neglected. The levelling of the bottom is obtained by the action 

 of the lower surface (belly and throat principally) together with 

 that of the hands." (Proceedings of the Zoological Society, 1895.) 

 The parents remain concealed near the nest till the time of hatch- 

 ing, which takes place in four or five days. Within their circular 

 " nursery " the tadpoles live till the adult stage is attained. 



When the eggs are small and numerous, as in ordinary Frogs 

 and Toads, hatching takes place comparatively early, and the 

 tadpoles are at first extremely helpless. They cannot even feed, 

 for the mouth is not yet properly developed, and the absence of 

 a tail in the earliest stage adds greatly to their disabilities. Some 



