14 RUDOLF SÖDERBERG, STUDIES OF THE BIRDS IN NORTH WEST AUSTRALIA. 
for the most part disappeared again very soon, but which nevertheless fertilized the soil, 
so that green grass soon began to sprout. In some places, however, those shallow 
collections of water remained for a considerable time, without outlet as they were, 
lying spread like small lakes or ponds. Such was the case in the neighbourhood 
round our residence, which was like an archipelago in miniature, where small verdant 
islets were mirrored in the water. Those pools were not more than one foot deep, 
while the depth of the so-called »billabongs»> might be one meter or more. These 
latter were situated in larger depressions, which collected the water from brooklets. 
Here the vegetation became comparatively rich with knolly formation on the edges 
recalling little sedge-meadows. As another example of the destructive violence with 
which the storm had swept through the wood may be mentioned the fact that here 
we saw a common species of foliage-trees (eucalyptus?) standing black, as through 
burnt, with the leafage devastated. The leaves were torn at the edges and presented 
an appearance recalling young oaks touched by the frost in our own country. The 
water was in all of the billabongs yellow and muddy and remained so all the year. 
On the bare areas, where the water had dried in there was a hard crust, criss-crossed 
with cracks. The red laterite-earth held particles of clay, which had been puttied 
together to that hard crust. At first it was still so brittle that it would not bear 
a person's weight. The ground was everywhere thoroughly drenched and soaked 
under the surface. 
The animal life had quite changed from what it was before the rains. From 
the water-pools the noise of a great number of batrachias was heard even the day 
after the storm. Soon they filled almost every puddle so that it was as if the air 
vibrated with their ceroaking, which sounded night and day. The whole landscape 
seemed to be changed into a frog-marsh. TI have distinguished five different kinds 
of croaking, jarring, vibrating, and trilling cries, and some sounding like bells, but 
I have not found more than two species of batrachias, both of them toads. They 
were always below the surface of water and never appeared above it.' 
The impression of the change in this previously silent nature seemed at first most 
surprising, especially when we remembered that the ground had been so dry and hot 
that nobody could have imagined what it harboured. Besides the noise of the toads, 
the air resounded with the chirping of the crickets and cicadas, in particularly at 
night when it rivalled in intensity with the croaking. As to the lower animals I 
remarked that butterflies began to appear, though very exceptionally. The neuro- 
pterans and the hymenopterans became rather common and on the dried parts of the 
ground there were lying long centripedes drowned by the flow of rain, and a few 
beetles as well. The lizards, which were very common, seemed on the other hand 
to have stood the inundation. (Many of them are also scansorial animals.) 
For the flies and the gnats too the right season was now come. They swarmed 
everywhere and became the torment that they alone can be. (ÅA severe eye-complaint 
caused by flies often annoys the traveller.) 
! Before the rains we never saw any batrachias out, but sometimes we had heard croaking from the 
hollow trees. 
