TO THE EMBRYOLOGY OF AMPHIBIA. 59 



small compared with the blastopore area. First ex-ovate had 

 been lost without leaving any trace; in its place a large globular 

 mass protruded anew. Blastopore lip grown considerably down- 

 ward. 



4:41 p.m. : — (Fig- d). Segmentation cavity no longer visible. 

 Blastopore considerably reduced in size. Large ex-ovate in 

 front, and to the right of the now faintly recognizable 

 medullary plate. 

 May 7, 9:30 a.m. : — (Fig. e). Medullary groove and folds evident. 

 Ex-ovate in front. 



4:27 p.m. : — (Fig. /). Embryonic body distinct, shorter than nor- 

 mal. Medullary groove ready to be closed. Ex-ovate a short 

 distance in front of the head end. 



The shortness of the embryonic body is probably due to the 



exudation of the second large ex-ovate. The development is 



otherwise normal. Compare Diagram Fig. 83. 



Egg No. 10. (Figs. 75 a-f, Fig. 84). 



{Cf. Egg No. 5). 



May 5, 2:43 p.m. : — (Fig. a). Punctured on the ventral median line, 

 approximately 45° below the equator. 

 4:26 p.m. : — (Fig. b). Normal. 

 May 6, 8:46 a.m. : — (Fig. c). Blastopore circle complete. Ex-ovate at 

 its ventral lip. 

 4:45 p.m. : — (Fig. (/). Area of the segmentation cavity vanished. 

 Blastopore much smaller and the ex-ovate attached to its left 

 dorsal margin. 

 May 7, 9:30 a.m. : — (Fig. c). Blastopore nearly closed, leaving a small 

 yolk-plug. Ex-ovate out of the blastopore, but still closely 

 attached to the dorsal lip. Neural plate faintly visible. 

 4:30 p.m. : — (Fig. /). General outline of the embryo formed. 

 Ex-ovate attached to the posterior end of the left neural fold. 



We must conclude that the blastopore was finally closed at 



the point of injury, the ventral lip ceasing to grow when it reached 



the ex-ovate about 45° below the equator, the task of overgrowth 



