12 ART. 3. S. IKEDA I CONTRIBUTIONS 



microscope. Also a small amount of blue-black pigment makes 

 its first appearance in the pectoral region at this stage. 



Fig. 19 represents a greatly advanced tadpole on the eleventh 

 day after deposition. At this stage, the larvae which measure 

 l£-2cm. in length are already escaped into the water together 

 with the melted frothy substance. They are now sprinkled with 

 a large amount of pigment not only at the pectoral region but 

 also along the dorsal surface of the head and of the thoracic- 

 region. The blood-vessels on the surface of the yolk-mass and 

 along the mid-lateral line of the larval body are conspicuous. In 

 the fully grown tadpole, however, the blood-vessels as well as the 

 heart become entirely invisible, on account of the dense pigment 

 accumulated as usual within- the skin. The suctorial discs are 

 rather rudimentary and appear late as a pair of small papilla-like 

 spots in front of the mandibular arches. Such incomplete forma- 

 tion and retardation in appearance of the suctorial discs are 

 probably due to the fact that the eggs are deposited underground 

 and out of water. Only when the tadpoles escape into the water, 

 is the necessity of some attaching organ felt. 



Recently Budgett ('99) has called attention to the probable 

 similarity in development of Rhacophorus as given by myself in 

 my former paper and of Phyllomedusa hypobrauchialis as described 

 by him. He says : " * * * from what he (Ikeda) mentions of 

 the appearance of the embryo which develops in a froth much 

 as is the case with Palidiocola, I think the development of this 

 form will be found quite like that of Phyllomedusa." Basing my 

 judgment on the description and figures of Phyttomedusa given 

 by Budgett, I may perhaps point out the points of similarity 

 and difference between that genus and Rhacophorus, some of 

 which are by no means insignificant. 



