102 ERNEST WAUKEN. 



(cci.j) of the embryo is in intimate contact with the placental tissue 

 ipl. t). 



Fig. 18. - X 220. Longitudinal section of gonangium at right angles 

 to the plane of flattening. The planula is seen wedged between the 

 perisarc of the gonotheca. The wall of the planula is very thin laterally. 

 Init much thicker proximally and distally. 



Fig. 19. — x 220. The planula in section in the plane of flattening 

 of the gonotheca. The wall of the planula is of considei'able thickness 

 all round. Both the endoderm (f»fZ.,) and ectoderm (cct.-^) are several 

 cells in thickness. 



