344 MOSTLY MAMMALS 
in the world. Doubtless glad to be free from her charge, 
the mother-toad thereupon rubs off what remains of the 
cells against any convenient stone or plant-stem, and 
comes out in all the glory of a brand-new skin, only, 
before long, to undergo the whole process over again. 
The Surinam toad is, however, by no means the only 
South American representative of its order whose nursery 
arrangements are peculiar, a considerable number of frogs 
and toads from, the warmer regions of the New World 
having ideas of their own as to the proper method of 
bringing up a young family. Among these are certain 
species nearly allied to the familiar tree-frogs of Europe, 
but differing in that the females have a large pouch for 
the reception of the eggs. Unlike the kangaroos and 
other mammalian marsupials, in which the female has her 
nursing-pouch on the under-side of the body, these mar- 
supial frogs (JVototrema) have this receptacle placed on the 
back, at the hinder end of which it forms a half-open 
tunnel, with its aperture directed backwards, although the 
pouch extends beneath the skin of the whole of the upper 
surface of the body. In this capacious nursery are deposited 
some fifteen or sixteen large eggs, which in due course 
develop into complete little frogs, without living tadpoles 
being produced, although at a certain stage the large eyes 
and long tail of a veritable tadpole are visible through the 
clear covering of the egg. 
According to a communication made by Dr. Goeldi, of 
Rio de Janeiro, to the Zoological Society, the tree-frogs 
of the genus Ayla inhabiting that part of Brazil show 
considerable diversity in regard to nursing habits, although 
none of them have any part of their own body modified 
into a nursery. One species, for instance, builds nests of 
mud on the shallow borders of pools, wherein the eggs 
