HORN EXPEDITION—AMPHIBIA. 
165 
In the burrow the animals have the dull colour previously described ; after 
rain has fallen they come to the surface and must start breeding at once. In all 
probability they are capable of burrowing and lestivating at a comparatively 
young age, for though they grow rapidly, the water-holes evaporate often in a 
very short time, and they were not found in any of the permanent pools amongst 
the ranges. In clay-pans and holes along various creeks, where the banks were 
made of clayey sand and were thus fit for their burrows, they are found after rain 
in various stages of development. There is first the full-grown form, which is 
often puffed-out and swollen, but at this time not with water ; secondly, there is 
the half-grown and very lightly-coloured animal, and thirdly there is the tadpole 
in all stages of development. Unfortunately I have not been able to secure either 
the eggs or the very young form—to do this you must be on the spot within a day 
or two of the fall of rain, as the excessive heat renders the development a very 
rapid one. The more rapid the development the better chance the animal has of 
surviving. In January and February many of the water-holes were swarming 
with tadpoles, an enormous number of which perish as they dry up ; it is only in 
the somewhat deeper ones that the animals can possildy live long enough to enable 
them to attain to the burrowing stage; and, as a general rule, only the most 
rapidly-developing ones which can do this. 
In such parts as Central Australia it might have been thought that frogs 
would have developed without the necessity of passing through a water-living 
stage, but there is here no alternative between an extremely wet and an extremely 
dry condition. In other moister parts of Australia, such as Gippsland in Victoria 
for example, there is moisture enough retained under the shelter of fallen logs to 
serve the purpose, so that here certain frogs, such as species of Crinia, do not lay 
their eggs actually in water but in damp spots under logs and stones. But in 
Central Australia, except when rain is actually falling, the only spots which are 
damp lie in the water-holes themselves. A foot away from these everything is as 
dry as possible, and so it is essential that the eggs should be laid in the water-holes, 
for if they were not they would immediately be dried up. It is probably in the 
moister rather than in the very dry country that we might expect a water-living 
stage to be absent in the life-history of a frog. 
(3) Chiroleptes brevipalmatus^ Gunther. 
This species was only found on one occasion in the adult state. While digging 
the earth out around the root of a gum-tree (E. rostrafa) at the very edge of a 
water-hole in course of drying up I came upon eight specimens all buried in hard mud 
