THE PRODUCTION OF GRAFTED EMBRYOS. 83 



are shown in Figs. 10 and u. The blastula, gastrula, and 

 young pluteus are shown in Figs. 12, 13 and 14. It need hardly 

 be iterated that the eggs and embryos in the control cultures 



23 24 25 



31 

 FIGS. 23-32. 



varied within certain limits, as carefully worked out by Tennent 



{'10); the above figures represent typical or average specimens. 



The treated eggs differed from the controls, in being elongated 



