Igog] MCALLISTER—EMBRYO SAC OF SMILACINA 215 
Fic. 4.—Formation of cell plate and daughter nuclei at the close of first 
_ division of mother ce 
2 
. 
; 
i cal et FS 
Fic. 5.—Early metaphase stage of homotypic division; axes of spindles 
oblique. 
Fic. 6.—Daughter nuclei and cell plates f 
outer daughter cell dividing transversely and inner one longitudinally. 
Fic. 7.—Nuclei of second division fully formed, arranged bilaterally; division 
membranes of second division do not reach outside walls. 
Fic. 8.—The outer daughter cell has divided longitudinally and the inner 
one transversely. 
FIGs. 9, 10.—Two successive sections of the same nucellus, showing the division 
of an approximately spherical mother cell; hete rotypic division longitudinal; 
one daughter cell in the homeotypic division dividing longitudinally and the other 
transversely. 
Fic. 11.—Row of four very large megaspores, with the division =e very inde- 
ite. 
Fic. 12.—Commonest arrangement of megaspores, in which first division is 
oblique and second at right angles to first; walls have disappeared but plasma 
membranes still persist. ae 
IG. 13.—Four megaspores; a cleft between two middle nuclei is all that 
remains of division membranes of cells. é 
Fic. 14.—Four megaspores, with no traces of cell walls, forming four-celled 
Stage of embryo sac. 
Fics. 15, 16.—Stages in the vacuolation of the four-celled embryo sac. 
Fic. 17.—Eight-celled embryo sac, showing micropylar and antipodal groups 
of nuclei, the two polar nuclei already separated out. 
] £ d divician: 
’ 
