HORN EXPKUrnoX NAKIIATIVi:. 2o 



Ju suiuc forms, .such as Ampliibuliinis pichis, \\ culoured drawijiy of wliirli 

 accoiii|);uii(_'S tilt; ai'tich; of Messrs. Lucas and Fi'ost in tlic Zoological section of the 

 work, the males coukl now be always readily distinguished hy tiieir more strongly 

 marked colouration from the females. In .[. iiiaciilatus the ditl'erence is still more 

 striking, the jet-black patches on the under surface of the male ai'e entirely 

 wanting in tiie female, and the two sexes can be distinguished at a glance. 



Tiiis often i-e:dly brilliant colouration has apparently nothing to do with the 

 colour of their environment, indeed to human eyes it renders them more easily 

 seen, and this at a time when their eneniiijs the birds arc especially abundant. 



Ailaptation to their environment for protective pui'poses is evidently by no 

 means the princi|)al determining facbtr in the colouration of these lizards. This 

 brighter colouiation which is strongly marked in both sexes but especially, as 

 usual, in tiie male is to Ije associated with the peculiar activity of tlu^ chemical 

 processes taking i)lace in the skin as in all parts of the; animal. In the dry season 

 food is scarce and the animals become lethargic and dull coloured, in the I'ain 

 season food is abund.ant, every animal is at work gorging itself, all its activities 

 are at the highest pitch and intimately associated with the suui total of its 

 activities and the necessary great increase of chemical activity in every organ and 

 part of thf! body is the development of Ijrightly coloured pigments. Th.at these, as 

 in the case sometimes of the frogs, niay lit in with the colours of the environment 

 and so, perhaps, to a certain e.xtent, serve for protection is a secondary matter. 

 Any(jne who has collected such animals as .-Imphibolums pictus will have brought 

 home to him the fact that brillant colouration is ofteii the accompaniment of a 

 general state of activity, and that it has, at all events in many cases, nothing 

 whatever to do with that of the surroundings. 



Though in tin; tlry season a general yellowish colour is ehara,eteristic of many 

 form (such as the species of Amphibolurus allude<l to) which are found on the sand- 

 hills and stony and loamy plains, still theix: is really no difficulty, so far as human 

 eyes are concerned, in seeing a, lizard, and, in the bi'eeding season, they become 

 brightly tinted with colours such as blue which does not exist in their environment. 



Forms such as Gcliyra varicj^^afa and Ilctcronuta byiioei, which are often 

 beautifully coloured, habitually, at all events in the; day tiuic, stay under logs and 

 stones and are never seen in the open. (Jne form — a new one — which we found 

 ( Vartunis i^i/leni) climbs the trunks of desert oaks and gum trees, and with its 

 purplish-grey tinge may perhaps secure a certain amount of concealment; but if 

 you are on tiie look out for them it is really very rarely that you tind your.self 



