662 
president's address. 
immigrants from very various directions. The new light thrown 
upon these matters by the naturalists of the Horn Expedition is 
one of the distinctive features of the Report. We get as it were 
hints and glimpses of adaptive relations to special surroundings in 
studying the fauna of the inland portions of the eastern colonies, 
but in Central Australia they reach a maximum. Here the 
struggle for existence takes on a new aspect. It is on the whole 
perhaps not so much a struggle among individuals as a struggle 
against climate, and all that that involves. As Darwin says : 
" When we reach the Arctic regions, or snow-capped summits, or 
absolute deserts the struggle for life is almost exclusively with 
the elements" (Origin, 1st Ed. p. 69). In Central Australia 
when a really good time comes, though some species have their 
numbers kept down by predaceous enemies or by a percentage of 
their progeny failing to complete their development in time, it 
must, though short, still on the whole be a very good time for a 
considerable proportion of the fauna. 
When the drying-up process sets in again, then once more 
begins the struggle against the elements, and the need for special 
adaptation comes into play. The larger mammals endowed with 
great vitality, such as the kangaroo and the dingo, must weather 
it out or travel. The smaller mammals are nocturnal in their 
habits, often burrowers, able to put up with a minimum water 
supply, and a diet of ants or of dry herbage. The frogs are 
especially interesting as having in most cases superadded to a 
strongly marked burrowing habit a remarkable capacity for 
storing water within their bodies. The fishes are favoured in 
another way. In South Australia, Victoria, and Tasmania is 
found the pouched lamprey ( Geotria ) which in dry seasons is said 
to fill its remarkably developed throat-pouch with water, and then 
to sestivate buried in the mud. Of the Central Australian fishes 
Mr. Zietz is unable to report anything so striking as this. The 
piscine inhabitants of isolated shallow pools become extinct in dry 
periods, but others survive in the deeper permanent holes whence 
they may be afterwards again distributed by floods. Like the 
Batrachia, too, they have another string to their bow in the 
