192 THE INFANCY OF ANIMALS 



bordering ponds. A basin-shaped hollow of mud is 

 scraped by the female to a depth of three or four inches, 

 the material removed being used to form a circular wall 

 or parapet which is carried up until it emerges above the 

 surface. The work of construction is performed with its 

 fore-feet, which may be likened to webbed hands, being 

 used for smoothing the inside of the wall as a mason would 

 use a trowel, while the floor is levelled by the action of 

 the belly and hands together. In this crater-like cavity, 

 which measures a foot in diameter, the eggs are deposited, 

 and here they remain protected against the attacks of 

 aquatic insects and fishes. 



A Japanese tree-frog {Rhacofhorus schlegelii) forms a 

 chamber a few inches above the water-level in the damp 

 earth on the edge of a ditch or flooded rice-field. After 

 smoothing the walls of the nursery the female produces 

 from the vent a secretion which, by rapid movements of 

 the feet, is rapidly worked up into a froth ; and in the 

 midst of this mass of foam the eggs are laid. The male, 

 who has all this time been clinging to her back, at once 

 fertilises them, and this done, the pair separate and make 

 their way out of the chamber by driving a tunnel which 

 slopes down to the water, the tunnel by which they en- 

 tered having closed up. The eggs remain protected and 

 aerated by the surrounding mass of foam for some days, 

 till the larvae have developed and are capable of inde- 

 pendent movement. 



By this time the walls of the nursery have collapsed, 

 forming a liquid stream which pours out through the 

 tunnel bored by the escaping builders, and in the stream 

 the larvae make their escape into the water, there to 

 undergo the tadpole stage. The eggs, it should be noted, 

 differ from those of the common frog in that the yolk is 



