470 EYVYCLESHVMER. [VoL. XIV. 
Five eggs were selected in the crescentic blastopore stage, 
and punctured at a short distance below the centre of the 
blastopore, as shown in Figs. 25, and 31. Of these but two 
were satisfactory. The successive positions occupied by one 
of these are shown in Figs. 25-27, while those occupied by the 
other are shown in Figs. 31 and 32. 
Three eggs in the stage of crescentic blastopore were punc- 
tured at points some 15° to 20° above the blastopore, as shown 
in Figs. 33 and 35. Two operations were successful. In one 
egg the exovate was later found within the caudal portion of the 
neural fold and near the median line, as shown in Fig. 34. In 
the other (Fig. 36) the exovate lay in the fold and at the left 
of the median line. 
Four eggs in the crescentic blastopore stage were punctured 
below the middle of the blastopore, and in the immediate 
vicinity of the lower pole, as shown in Figs. 37 and 39. Two 
eggs developed normally. The exovate in one case occupied a 
position just below the posterior end of the embryo, as shown 
in Fig. 38. In the other (Fig. 40) it lay much farther below 
the posterior end of the embryo. 
Series II. — Bufo lentiginosus. 
May 5, 1895, five eggs in the early gastrula stage were 
punctured just below the equator and above the centre of the 
crescentic blastopore. . The results are shown in Figs. 41-45. 
In all cases the exovates lay behind a transverse line marking 
off the posterior third of the length of the embryo. The varia- 
tions existing in the position of the exovates, with reference to 
the median plane of the embryo, were probably due to the fact 
that the ends of the crescentic blastopore progressed at such 
varying rates that it was difficult to locate the meridian which 
passes through the centre of the blastopore. 
In five eggs in late cleavage, punctures were made at the 
upper pole. Four of these developed. The positions of the 
exovates are shown in Figs. 46-49. In these cases they were 
in or near the transverse portion of the neural fold. 
In ten eggs at the same stage, punctures were made in the 
same locality. In each of this lot a second puncture was made 
