326 J. S. BUDGETT. 



amount of food-yolk, as it can hardly be supposed that, at a 

 stage previous to hatching in either mode of development, 

 Phyllomedusa should be more primitive than the free-swim- 

 ming forms. 



I think the median spiracle may also be looked upon as 

 a primitive feature. 



The manner in which the branchial fold encircles the 

 head reminds one strongly of Salensky's figure of Acipenser 

 at a similar stage. 



From tl)e study of the development of Phyllomedusa, of 

 which I have described the points of more general interest, 1 

 am distinctly inclined to think that we are not always war- 

 ranted in attributing to alecithal free-swimming larvse a 

 greater biological importance, as far as retaining ancestral 

 characters is concerned, than to heavily yolked embryos. 



I think, moreover, that this is what we should expect, for 

 from the time that the larva is hatched onwards it is subjected 

 to the influence of natural selection. 



Indeed, in this particular case of Batrachian development it 

 would seem rather that the shortening of the embryonic period 

 may be a specialised and not a primitive condition. 



The fact that the majority of frogs have a shorter embryonic 

 life does not seem to me to prove that the minority are the 

 specialised forms in this respect. This particular mode of 

 development is not confined to this species. 



Von Jhering has described the oviposition of Phyllome- 

 dusa Jheringii, which agrees very closely with that here 

 described. The eggs were laid between two or more leaves 

 instead of being rolled in one, as with Phyllomedusa hypo- 

 chondrialis. Von Jhering did not, however, work out the 

 development of this species ; in all probability it would not 

 differ from this one. 



This year S. Ikeda, of Tokio, has published an account of 

 the oviposition in a species of Rhacophorus ; from what he 

 mentions of the appearance of the embryos which develop in a 

 froth, much as is the case with Paludicola, I think the deve- 

 lopment of this form will be found to be quite like that of 



