PLATE II. 



Fig. ro. Oblique section of an embryo-sac of A. simplex, with two nuclei, at 



the lower end of the sac. x 250. 

 Fig. II. Ovule of A. simplex vf'iXh. an embryo-sac containing an egg apparatus 



and two free nuclei. x 40. 

 Figs. 12, 13. Details of the embryo-sac shown in fig. 11. 12 shows the egg (c>) 



and the two free nuclei : 13, the synergidse. x 250. 

 Fig. 14. Section of an embryo-sac of A. sitnplex in which were two nuclei, 



only one of which is shown in the figure. The nuclei were beginning 



to divide. x 250. 

 Figs. 15, 16. Two sections of an embryo-sac of ^. commutaUim, with four nuclei, 



placed in pairs at the poles of the sac. 15 shows one of the micro- 



pylar nuclei ; 16, a chalazal nucleus. x 250. 

 Fig. 17. Micropylar region of an embryo-sac of A. commutatum of about the 



same age as that figured in 15, 16. 

 Fig. 18. Cross-section of the apex of an embiyo-sac of A. siinphx, showing the 



egg apparatus. x 250. 

 Fig. 19. Section through the central region of the same sac, showing one of the 



two free nuclei, x 250. 



