662 president's address. 



immigrants from very various directions. The new light thrown 

 upon these matters by the naturaUsts 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, Ist 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 (Geotrla) which in dry seasons is said 

 to till 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 



