lioiiN expedition—amphidia. 
155 
The forms which do burrow are those which, as in the case of the genera 
Chiroleptes, Heleioporus and Liinnodynastes, have a shovel-shaped metatarsal 
tubercle on the liind foot, such as the Hylas do not possess. 
There is probably a very frequent transport of the eggs of Amphibia from one 
water-liole to another. Immediately rain falls birds appear in great numbers, 
flying about from one water-hole to another. In one instance I saw a crow rise 
from the side of a water-hole with a pellet of earth attached to it fully three- 
quarters of an inch in diameter. In this way the eggs of frogs can easily be 
carried about. When once the floods sweep down the water-courses they carry 
away logs and shrubs for great distances, and along with these must go numbers 
of smaller animals. 
At intervals along the Finke River wells have been sunk, and around these 
little Hylas are always to be found, so that now, without burrowing, they can 
survive at isolated spots which will serve as centres from which other parts can be 
stocked in wet seasons. 
Whilst the Hylas and Limnodynastes ornatus were found in and around the 
wells, we never found the lai’ger frogs such as Chiroleptesplatycephalus here; in 
fact, the latter, as well as Helioporus pictus^ seems to prefer to live in parts where 
the water periodically dries up, so that they must burrow and lie dormant. 
Along with this burrowing habit has probably been acquired the capacity of 
I'apid development. Standing by a water-hole which is drying up one can easily 
realise the paramount importance which it is for the perpetuation of the species 
that the embryos should be able to develope as rapidly as possible, so as to reach a 
size at which they can take advantage of the abundance of food in the form of 
caterpillars, etc., which abound during a short space of time, and at which also 
they can form burrows. If they do not succeed in developing rapidly, then their 
chance of survival must be small indeed. 
The general conclusions to be drawn from our observations are:— 
(1) That Central Australia possesses but few species of Amphibia. 
(2) That these are in the main identical with certain forms found in 
the dry inland parts of Hew South Wales and Queensland. 
(3) That they are to be regarded as immigrants from the latter regions 
which have been able in the majority of cases to adapt them¬ 
selves to unfavourable climatic conditions by means of a marked 
