TO THE EMBRYOLOGY OF AMPHIBIA. 53 



In fact the development of the embryo in this egg is entirely- 

 natural and proves again the correctness of the observations before 

 recorded. Fig. 76 shows diagrammatical ly the location of the 

 embryo and the closing point of the blastopore. 



Egg No. 2. (Figs. 68 a-f, Fig. 77). 



May 5, 12:37 p.m. :— (Fig. a). Punctured a little to the left of the median 

 line, closely under the left limb of the dorsal blastopore lip. 



4:06 p.m. : — (Fig. b). Previously distinctly visible dorsal lip utterly 

 unrecognizable. Ex-ovate visible. Area of the segmentation- 

 cavity diminishing in the normal manner. 

 May 6, 8:02 a.m. : — (Fig. c). Blastopore with distinct lips, again 

 visible, closed in circle, but larger as compared with the same 

 stage of Egg No. 1 (Fig. 67 c). Ex-ovate attached inside the 

 blastopore near its left margin. In front of, and parallel 

 to the dorsal lip, another accessory lip present, formed perhaps 

 by the reappearance of the vanished original lip. Area of 

 the segmentation-cavity irregular in shape and found eccentric- 

 ally a little to the left of the median line, showing that the 

 rearranging process of the yolk-cells inside was disturbed. 



4:14 p.m. : — (Fig. d). Area of the segmentation-cavity entirely 

 vanished. Shape of the greatly diminished blastoporic area 

 triangular, being a little elongated dorso-ventrally. Ex-ovate 

 still attached within the blastopore near the left margin. 

 Accessory dorsal lip still visible and in its front the neural 

 plate and the shallow medullary groove faintly recognized. 

 May 7, 9:40 a.m. : — (Fig. e). Blastopore completely closed ; ex-ovate 

 still attached to the part where the blastopore closed. Ac- 

 cessory lip has now groivn around and enclosed a new 

 circidar patch in front of the actual closed blastopore. Em- 

 bryonic body raised a little over the egg-surface in front of the 

 accessory lip; comparatively short and somewhat incomplete. 



4:03 p.m. : — (Fig./). Embryonic body, medullary groove and folds 

 distinctly recognizable. Distal end of the medullary groove 

 has not yet reached the final closing point of the actual 

 blastopore, there being interposed the circular patch formed by 



