470 



L. S. STONE 



Fig. 58 Camera drawing, showing in dotted line and middorsal line in the 

 area of ectoderm removed at stage 23 in excising postauditory lateral-line pri- 

 mordia and epibranchial placodes of IX and X. The auditory placode was also 

 included. X 10. 



Fig. 59 Camerad rawing, showing in dotted line the area of blue implanted 

 ectoderm two days after operation, not including all the ectoderm along the pos- 

 terior border of the gill swelling. X 10. 



Fig. 60 Camera drawing ten days after operation, showing presence of a 

 ventral body line of sense organs when posterior border of gill swelling is not re- 

 moved as shown in figure 59. X 10. 



