720 Proceedings of the Royal Irish Academy. 



Fig. 9. — Pollen motlier-cell. Daughter chromosomes leaving nuclear 

 plate. Each, is seen breaking into two portions, x 500. 



Fig. 10. — Diaster in pollen mother-cell, x 500, 



Fig. 11. — Diaster in pollen mother-cell seen from the pole. A later 

 stage than Fig. 10. The chromosomes are breaking into 

 chromatin granules, x 500. 



Fig. 12. — Later stage than Fig. 11. Granules formed by the chromo- 

 somes before the formation of the complete daughter 

 nucleus, x 500. 



Figs. 13, 14, 15, Lilium chalcedonicum. 



Figs. 13, « and h.- — Nuclear plate of the second karyokinesis of the 

 pollen mother-cell appearing on two successive sections. 

 The chromosomes are undergoing longitudinal fission. 

 X 400. 



Fig. 14. — A similar preparation to Figs. 13 « and b. The whole 

 nuclear plate is contained in one section, x 500. 



Figs. 16-19, Lilium longifloriim. 



Fig. 15. — Embryo-sac showing the formation of the spindle in the 

 protoplasm outside the nucleus, x 400. 



Figs. 16, 17. — Two successive sections through the same embryo-sac, 

 showing the second karyokinesis. The chromosomes are 

 slender and longitudinally cleft. 



Fig. 18. — Upper portion of an unfertilized embryo-sac, showing the 

 direct nuclear fission occurring in the central portion. 

 X 260. 

 All the figs, are copies of drawings made by means of a camera 



lucida. 



