igi6] CHAMBERLAIN— STANGERIA PARADOXA 371 



7. Matte. H., Recherches sur l'appareil libero-ligneux des Cycadees. pp. 

 233. pis. 16. figs. 264. 1904. 



8. MlYAKE, K., Uber die Spermatozoiden von Cycas revoluta. Ber. Deutsch. 

 Bot. Gesells. 24:74-83. pi. 6. 1006. 



9. Pearson, H. H. W., Notes on South African cycads. I. Trans. South 

 African Phil. Soc. 16:341-354. ph. 6-8. 1906. 



10. Nash, G. V., A rare cycad. Jour. N.Y. Bot. Gard. 10:163, 164. 1909. 



11. Chamberlain, C. J., Spermatogenesis in Dioon edulc. Bot. Gaz. 47:215- 

 236. pis. 15-1S. 1909. 



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4i5"4- , Q- pis. 14-17- 1010. 



13. , The adult cycad trunk. Bot. Gaz. 52:81-104. 1911. 



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EXPLANATION OF PLATES XXIV-XXYI 



Most of the sections were cut at 5 /*; none was thicker than 10 /z. With 

 the exception of figs. 4-8, the drawings were reconstructed from two or more 

 sections. Figs. 12 and 13 are reconstructed to show all the nuclei of these 

 proembryos. 



Fig. 1. — Text cut, showing 5/(7 ngeria in the field. 



Fig. 2. — Nucellus with pollen tubes showing prothallial cell, stalk cell, 

 body cell with blepharoplasts, and tube nucleus; in one tube (at the right) 

 the body cell has divided; X50. 



Fig. 3. — Later stage: mature sperms are about to be shed; X 50. 



Fig. 4. — Blepharoplast, much vacuolated, shortly before breaking up 

 into granules; the body cell has not yet divided; X365. 



Fig. 5. — The blepharoplast has broken up into an immense number of 

 small granules; the nucleus of the young sperm is smaller than the blepharo- 

 plast of the preceding figure; the median portion of the spindle can still be 

 seen; X365. 



Fig. 6. — The granules have increased in size and number and are becoming 

 arranged into a flat band; note the great increase in the size of the nucleus; 

 X36 5 - 



Fig. 7. — Transverse section of a band at the stage shown in fig. 6; X365. 



Fig. 8. — The bristle-like cilia beginning to develop from the band; some 

 are directed toward the nucleus; X365. 



Fig. 9. — Fertilization: the sperm nucleus entering the egg nucleus; the 

 ciliated band remains at the top of the egg; X42. 



Fig. 10. — First mitosis in the fertilized egg: at the top, 3 sperms which 

 have passed through the neck, but have not entered the egg; the ciliated band 

 of the sperm which effected fertilization is easily seen; X42. 



