TO THE EMBRYOLOGY OF AMPHIBIA. 51 



7). The growth in length of the embryo in Bhacophorus 

 and other annran eggs takes place after the complete closure of 

 the blastopore or the finishing of the gastrulation process. 



IV. 



EXPERIMENTS BY PUNCTURE OF EGGS. 



After making out the normal course of development in the 

 anuran eggs, it occurred to me that experiments by puncturing 

 eggs would be interesting, if for no other reason than to determine 

 what effects these injuries would have on the normal course. Ac- 

 cordingly during the breeding season of 1900, some experiments 

 were made on the Rhacophorus eggs. 



The puncturing of the eggs was done with the sharpest possible 

 needles from the outside through the vitelline membrane and the 

 thin innermost compact layer of the frothy substance. The injuries 

 which I inflicted on the eggs proved on the whole rather severe, 

 but this was an advantage than otherwise, for slight punctures 

 heal rapidly and often leave no trace as has been observed by 

 many previous investigators. Moreover as remarked already by 

 Asshetox, punctures however slight have the effect of causing 

 eggs to deviate from the normal course, and if such is the case, 

 it is preferable to have the deviations stand out unmistakably by 

 making the injuries somewhat severe. 



I will anticipate the main result of these experiments by the 

 statement that the normal course of development can not be made 

 oat from the results obtained by the experiments. 



The number of eggs experimented upon was in all forty, 



