244 DAKIN, 



10.30 a.m. the water was swarming with tadpoles of the same advanced stage as 

 those from my experimental nests. Evidently the water had acted as the awaited 

 stimulus on the multitudes of unhatched tadpoles below the ground. The effect 

 was startling. Unfortunately the water was too salt. At 11.15 most of the tad- 

 poles were already dead, and a little later all had succumbed. The water sub- 

 sided during the afternoon, but the immersion hail killed off all the adults and not 

 a single croak has been heard from the garden since. My experimental nests 

 shared in the tragedy. Perhaps next year we may take steps to find out the 

 longest possible time the tadpoles can be kept without hatching, and what stage 

 can be reached by them. 



Comparison with Eastern species. So far as I know, the development of our 

 Heleioporvs is somewhat different from that of the Great Eastern Bun-owing Frog, 

 Philocryphus flavoguttatus, although the embryo id' this species is said to acquire 

 external gills before hatching. 



There is, however, some resemblance to the conditions described by Fletcher as 

 characteristic of Pseudophryne australis and P. Bibronii, species of Bufonidae, 

 except in so far as deposition of spawn is concerned. 



In these species, if the ova do not get into water the hatching is postponed 

 until they do. This period, according to Fletcher, may be as much as three or 

 four months. In this case, too, there seemed no indication of the metamorphoses 

 being completed, even when hatching had been very much delayed. 



Fletcher states that the eggs of Pseudophryne are deposited after rains "in 

 depressions or cavities, preferably under stones, but when these are wanting, under 

 pieces of old tin, etc." The same author remarks that one pole of the egg is pig- 

 mented black and there are no signs of externa] gills at any stage. These are 

 obvious differences from the stages in the Western Burrowing Frog, which is now 

 shown for the lirst time to be capable of a prolonged embryonic sojourn as a tad- 

 pole within tlie egg membranes. 



References:--.!. J. Fletcher, Oviposition and Habits of Certain Batrachians. 

 Tine. Linn. Soe. N.S.W., Vol. 4 (1889). pub. 1890. 



