HYLIDAE 



199 



sac ; and during the breeding season, which seems to occur during 

 our autumn and winter, develops brown rugosities on the inner 

 side of the first finger. The tongue is round, slightly notched 

 behind and free enough to be protruded a little. 



The alternative specific names are most unfortunately chosen, 

 as they apply only to spirit-specimens. During life this tree- 

 frog exhibits a considerable amount of colour -changes. The 

 normal colour is bright green above, white below. A conspicuous 



FIG. 39. Hyla coerulea. Australian Tree-frog (from photographs). Length of the 

 large specimen 4'2 inches. The upper right specimen with vocal sac inflated. 



feature of this species is the frequent occurrence of white specks 

 or spots, which are probably due to the deposition of guanine, 

 a peculiar white colouring matter. The spots appear in any part 

 of the green skin, and are quite irregular in their distribution. 

 Sometimes they remain for weeks in the same place, or they dis- 

 appear after a few days and others appear. They are in no way 

 connected with the shedding of the skin, nor do they indicate ill- 

 health. IT. coerulea lives well in confinement, and becomes tame 

 enough to take food from one's fingers, even when sitting upon the 

 hand. Some of mine took to living during the daytime in a small 

 box, preferring a crowded condition in companionship with Xatter- 



