THE EMBRYO 



299 



Fig. 170. Development of embryo of Scurrula atropurpurea. A, first division of 

 zygote. B,C, formation of biseriate proembryo; in B, the two terminal cells of 

 proembryo happen to overlap each other. D, proembryo penetrating inside endo- 

 sperm. E, enlarged view of terminal portion of proembryo of approximately same 

 age as D ; note beginning of differentiation between cells of suspensor and those of 

 embryo proper. (After Rauch, 198'!.) 



Fig. 171. Early stages in development of embryo of Balanophora abbreviata. A, 

 two-celled embryo formed by vertical division of zygote. B,C, more advanced 

 stages. (After Zweifel, 1939.) 



