AMPHIBIANS 437 



of importance in several ways. For it acts as a buoy, prevents 

 overcrowding, and by concentrating heat upon the egg hastens 

 development. It also serves as a protection against ducks and 

 other birds, owing to its slippery nature and bitter taste. 



A good many species lay their small eggs out of the water, 

 this being the case, for example, with a little Brazilian frog 

 i^Leptodactylus mystaciniis), which is purely terrestrial when adult. 

 Spawning takes place before the advent of the rainy season, the 

 mother scooping out a good-sized hole in the neighbourhood of 

 water for the reception of her eggs, which are surrounded by 

 a frothy mass that prevents them from 

 drying up, and also appears to serve as 

 food for the young tadpoles. They are 

 afterwards washed out of their nest by 

 the rain, and thus gain the adjacent pond, 

 where they develop into adults. Should 

 there be a drought the tadpoles live on 

 in the nest till the following rainy season. 



Some of the Tree- Frogs deposit their 

 eggs upon plants which overhang the 

 water, one or more leaves being folded 

 together into a sort of protective case. 

 Such an arrangement has been described Fig. g6i. -Egg-case of a Brazilian Tree- 



. .. Vxo%(PhyUomedusaJheringi) 



for a species ^Fhyuomeditsa J hermgi, hg. 



961) native to South Brazil, in which the eggs and the jelly by 

 which they are surrounded are wrapped up in willow leaves. 

 The tadpoles hatch out in this hanging nest and drop into the 

 water below. 



The two species last described display a certain amount of 

 parental care, but are far surpassed in this respect by a Brazilian 

 tree-frog i^Hyla faber) known locally as the " Ferreiro ", i.e. 

 "Smith", on account of its curious voice, the sound of which has 

 been compared to that produced by a copper plate beaten with 

 a mallet. The female makes a circular nest in the shallow water 

 at the edge of a pond (fig. 962), one or two nights being required 

 for its construction. We are indebted to Goeldi for our know- 

 ledge of this interesting habit, of which he gives the following 

 account, based on observations made in his own garden at Para: 

 " We soon saw a mass of mud rising to the surface carried by 

 a tree - frog, of which no more than the two hands emerged. 



