BY J. J. FLETCHER. 379 



These phenomena, may, however, be pathological, as the individ- 

 uals sometimes seem sickly, and may have nothing to do with 

 respiration ; but I have never seen anything like it in tadpoles 

 of other species.] Development proceeds steadily, the tadpoles 

 becoming more and more recognisable, until after between a 

 fortnight or three weeks from the time of laying they are 

 ready for hatching. By this time in order to accommodate 

 itself to the size of the chamber in which it lies the tad- 

 pole bends its tail round to one side, the tip reaching to the 

 snout or beyond ; from time to time the position is changed 

 by bending the tail the other way. If now a number of the ova 

 are placed in water some of the tadpoles will emerge very shortly^ 

 while others may not do so for a day or two. They emerge 

 through a usually more or less circular hole ; but I have never 

 been able to observe the actual exit thouo'h I have watched 

 for it, and have several times seea them with the tail free, 

 but these may be cases of misadventure. Possibly the tadpole 

 with its horny beaks first weakens a spot in the envelope 

 softened by moisture, and then deliberately increases the strain, 

 as Royer describes in Alytes (I.e. p. 428). If the ova do not 

 get into the water the hatching is simply postponed till they 

 do, a proceeding which at any rate for a period of at least 

 three months, provided of course that they are not absolutely 

 deprived of moisture, seems to cause little inconvenience. They 

 can stand a good deal of dessication without damage ; and anyone 

 who sees specimens which have undergone some drying up for the 

 first time would hardly believe that the contained tadpoles are 

 still alive ; nevertheless on the addition of water the gelatinous 

 matter again swells up as before ; under these circumstances if the 

 ova are left in the water the tadpoles seem to hatch more quickly 

 than otherwise. 



Balfour in his Comparative Embryology (Vol. II. p. 115) 

 mentions the large yolk-sack of Pseudophryne australis. This is 

 evidently correlated with the ability to endure a postponement of 

 the hatching. Oviposition takes place after heavy rain, and the 

 next fall of rain has to be depended upon for the release of the 



