IIOUN EXPEDITION NARRATIVE. 27 



dull Idowii ur grey, (.lie briglit yellow markings on the Hanks and sides of the hudy 

 being only visible when the animal moves. It must, however, be noted that these 

 frogs remain close to the water's side on the sandy or, in wet weather, muddy bank, 

 and usually shelter under stones. 



The impression which is left upon one after collecting these Central Australian 

 animals in both the dry season, when they are iluU coloured and in the wet 

 season, when they are brightly coloured, is that the often remarkable change in 

 colouration is of very little service so far as protection is concerned, even when the 

 change in colour is such as to produce a geneial resendjlance between tln^ colour of 

 the animal and that of its surroundings ; whilst in certain cases, such as that of 

 the lizard Ainpliibolitnts picius, the brighter colours render the animal more 

 conspicuous to human eyes and presumably to such enemies as the snakes, who 

 certainly feed upon it. 



It is, fui'ther not perhaps without interest to note that the change from a dull 

 to a brilliant colouration takes place at or about the breeding season in the case of 

 the frogs and lizards, but that this change, which is really just as striking as in 

 that of many birds, has nothing wliatever to do with the choice of partners. 



Sometime, as in the frogs and certain lizards (such iva Ainphibolunis rcticulatus) 

 it affects equally the male and female, while in others (such as Ainpliibolurus picliis 

 and A. iiuia(latiis) the male is more affected than the female. 



This change in colouration actually takes place quite apart from and indeetl 

 reaches its highest development after pairing has taken place. What happens in 

 the case of the Central Australian frogs and lizards is that the moment the rain 

 falls the animals become active — the frogs come out of their hiding places — and at 

 once pairing takes place. Every animal sets to work to feed and to reproduce its 

 species, and in this state of general activity l)oth male and female rapidly, but 

 independently of, and as before said, subsequently to, pairing assumes its brightest 

 colours. 



In the warm dauqj ground the seeds rapidly germinate. In a wonderfully 

 short time the bare loamy ])Liin and even the stcjny gibljer-tield becomes greiMi 

 with herl)age ; caterpillars and adult insects appear in myriads, frogs and lizards 

 feed upon the insects whilst birds and snakes devour the frogs and lizards. 



A study of the Central Australian fauna leads onc^ to the following main 

 conclusions with regard to colouration : — 



