132 



rl. Thomas Patterson. 



25 



Fig. 25. — Blastodisc showing sixty-four cells in surface view — forty-one 

 central and twenty-three marginal (see Table 1, hen No. 7). X 18. 



«c 



26 



Fig. 26. — Median longitudinal section of a blastoderm in a stage of devel- 

 opment corresponding to that of the preceding figure, s.c, segmentation 

 cavity. X 55. 



