426 TRANSACTIONS AND PROCEEDINGS OF [Sess. lvi. 



antipodal cell, A. C, which are separated from one another, 

 by a plate, PL, showing on focussing an anterior, a, and 

 a posterior, ^j, margin. 



Fig. 19. Ditto; the antipodal cell, A. C, shows a vacuole, r. 



Fig. 20. The antipodal cell, A. C, precedes its sister-cell, M. C, in 

 division as proved by the more advanced karyokinesis. 



Fig. 21. The micropylar portion of the embryo-sac M. C, with two 

 nuclei, separated from the lower antipodal portion, A. C, 

 1)y a plate, PI. 



Fig. 22. Ditto. The membrane ni^ is formed before the mem- 

 brane 1)1^. 



Fig. 23. Ditto. Several hyaline bodies, //. B., in the micropylar 

 cell, M. C. The two nuclei of the antipodal cell sepa- 

 rated by a vacuole, v. 



Fig. 24. Young embryo-sac giving rise to the typical number of 

 eight nuclei — two will form the synergidse, syn. ; two the 

 ovum, Of. -f apical primordial cell, a. p. ; two the anti- 

 podes, ant.; two the third antipode and antipodal prim- 

 ordial cell, ant. -Hja V., The central vacuole. 



Fig. 25^*. Embryo-sac with two sjTiergidte, syn., one ovum, ov., 

 and micropylar primordial cell, m. j^. c, in its apical 

 portion, 7n. ; three antipodes, 3 ant. , and an antipodal 

 primordial cell in its basal portion, a.; i-i, septum be- 

 tween the two basal antipodal cells and the tliird anti- 

 podal cell + the primordial cell. V., vacuole. 



Fig. 25^ Ditto. PerfW. = periblem cells derived from the non- 

 physiological archesporia, and cap, cap, derived from 

 the non-physiological embryo-sacs. deg. c. = degenerating 

 periblem cells. P, level at which wall of vacuole is 

 without a covering of plasm, M. N., nucleus of micropylar 

 primordial cell. a. p. c. = antipodal primordial cell. 



Figs. 26'^~'', 27^'^ Same lettering. Showing the amoeboid processes 

 sent out by the two primordial cells. Pi. Fig. 27**, I., 

 separation of antipodal cell from the nucellar cells. 



Fi". 28. Later stage, with vacuolation of synergidaj and ovum, 

 and fusion of the protoplasm of the two primordial cells. 



Fi'f. 29'^"*' and fig. 30 re])roseut the gradual approach of the nucleus 

 of the antipodal primordial cell, A. N., for purposes of 

 fusion with the micropylar nucleus, M. N. 



Fig. 31. Mature embryo-sac with a fully formed primary endosperm 

 nucleus, p. e. n., occupying the centre of the endosperm 

 cell, E. a 



Figs. 32-45. Various stages in tlie formation of the primary endo- 

 sperm nucleus. The following lettering holds good for 

 all figiires : M. N., micropylar nucleus; A. N., antipodal 

 nucleus; nuclear membrane, n.m.; peripheral chromatin 



