TO THE EMBRYOLOGY OF AMPHIBIA. 55 



cognizable. Blastopore already closed leaving a small yolk- 

 plug. Ex-ovate detached and adhering to the inner face of 

 the vitelline membrane, but its scar still visible as a plug-like 

 protuberance of the yolk substance in front of the normal 

 yolk-plug. Embryonic body shorter than normal. 



The first effect of puncture in this egg seems to have been 



a sending upward of the dorsal blastopore lip toward the point of 



injury. This was probably due to the exudation of more or less 



yolk substance in the intervening space. The dorsal lip does not 



seem to have grown downward at all after this, thus causing a 



peculiar pointed bay in the blastoporic area. The growth over the 



yolk seems to have been undertaken entirely by the ventral and 



lateral lips. The whole of the embryo was without doubt formed 



entirely on the upper hemisphere, as in No. 2. Fig. 78 represents 



diagrammatically the location of the embryo body. The oblique 



dotted line indicates the part over which the dorsal blastopore lip 



was pulled upward. 



Egg No. 4. (Figs. 70 a-f) Fig. 79). 



May 5, 2:43 p.m. : — (Fig. a). Punctured on both sides of the dorsal 

 blastopore lip slightly below its level, and at about equal 

 distances from it (the right puncture just a little nearer and 

 heavier, hence its ex-ovate larger). 

 4:14 p.m. :— (Fig. b). No noteworthy peculiarity. Translucent area 

 grown smaller. Dorsal lip grown slightly downwards. 



May 6, 8:19 a.m. : — (Fig. c). Blastopore circle completed but very 

 peculiar in appearance. Two horns sent outward from its 

 upper lateral corners to each ex-ovate. Dorsal lip curved 

 contrary to the usual way and has a hanging festoon-like 

 outline, showing that the middle point is growing fastest 

 downward. Segmentation cavity of an unusual shape, being 

 elongated antero-posteriorly and somewhat out of the median 

 line on the left side. 

 4:22 p.m. : — (Fig. d). Segmentation-cavity entirely vanished. 



