380 OVIPOSITION AND HABITS OF CERTAIN BATRACHIANS, 



tadpoles; but the intervening period may be one of weeks or 

 months. On July 29th, 1885, I exhibited at a meeting of this 

 Society [vide Proceedings x, p. 342] ova of P. hihronii (not P. 

 australis as there mentioned) obtained in the previous April, that 

 is to say a period of between three and four months, yet the 

 tadpoles seemed to be none the worse ; after reaching the con- 

 dition of readiness for hatching they increased but little in size, 

 and there was a marked difference in this respect between tadpoles 

 of the same batch allowed to hatch at different tioies. I have not 

 yet ascertained the limit of endurance, but it was certainly not 

 reached in the above case. The only dii3iculty to be contended 

 with is to keep the ova sufficiently moist and yet keep them free 

 from attacks of moulds. I kept them in the hope of seeing them 

 complete their metamorphoses without gaining access to water ; 

 this however they seem unable to do. The tadpoles are very 

 hardy, strikingly so as compared with those of other species. A 

 number of them may be hatched out in a wine-glassful of water 

 and left for a fortnight or longer without the water being changed 

 or any food supplied, and yet they seem none the worse for such 

 treatment which would be fatal to ordinary tadpoles. 



The above-mentioned facts explain the sudden appearance of 

 large numbers of the tadpoles in pools and ponds after heavy 

 rains, which when previously visited were dry or contained no 

 tadpoles, and when the intervening interval has been too short to 

 allow development to have reached the stage met with. I have 

 met with instances of this kind frequently, but the tadpoles have 

 always being referable to one or other of the species of Pseudo- 

 phryne ; and I have seen nothing to warrant the supposition that 

 the tadpoles of other species by burying themselves in the mud 

 can survive for any length of time if, as frequently happens, the 

 ponds dry before the completion of the metamorphoses ; if they 

 could one would expect to find instances of their sudden re-ap- 

 pearance after rain has again filled the ponds. Balfour (I.e. p 116) 

 also says : " The tadpoles of Toads are the smallest, Pseudo- 

 phryne australis excelling in this respect." When hatched the 

 tadpoles of both species are about 10 mm. long of which the 



