220 HUBERT DANA GOODALE 



true for the eggs marked about the equator. In a few experiments 

 the upper four cells at the eight-cell stage were destroyed. No 

 embryo developed, although some gastrulated. 



The embryos which developed in an oblique position on the 

 upper hemisphere in some eggs marked about the equator and 

 described below, appears to be correlated with shiftings of the 

 blastopore, although the data is too scanty to determine this 

 with certainty. 



The results from the 16 successful eggs were somewhat vari- 

 able. The tran'sverse neural folds formed either at the original 

 upper pole of the egg or at some point not over 40° beyond. 

 Part of this variation may be ascribed to difficulties in exactly 

 locating the upper pole. But as the blastopore has been found to 

 move in varying amounts and as the embryo when first formed 

 varies somewhat in length, the differences are partly real. 



42 43 44 



Owing to lack of space only two eggs can receive individual 

 description. In tffe figures, the stained places are indicated by 

 stippling. The closer the stippling, the stronger the stain. How- 

 ever, the relative differences of stain indicated, are, as a rule, 

 applicable only to the figure to which they belong. 



Series A. No. 1. Eggs in 12 to 32 celled stage, marked May 9, 

 8 P.M. First drawing made next morning, 6.45 a.m. Fig. 42 shows 

 the stained areas as a sort of hollow square on the upper hemis- 

 phere, with a projection to one side. Three of the corners are more 

 heavily stained. About thirty-four hours later, the stain appeared 

 as shown in fig. 43. As the stain remained nearly constant, no 

 further drawings were made until May 14, 8:30 a.m., when the 

 embryo was well developed (fig. 44). The anterior connective 

 lies in about the middle of the stained area. 



