i9*>] SHARP— SPERMATOGENESIS . 267 



4. Chamberlain, C. J., Spermatogenesis in Dioon edule. Bot. Gaz. 47: 

 215-236. pis. 16-18. 1909. 



5. Henneguy, L. F., Sur les rapports des cils vibratiles avec les centrosomes. 

 Arch. d'Anat. Micr. 1:481-496. figs. j. 1898. 



6. Ikeno, S., Die Spermatogenese von Marchantia polymorpha. Beih. 

 Bot. Centralbl. 15:65-88. pi. 3. 1903. 



7. Minxhin, E. A., An introduction to the study of the Protozoa. London. 

 1912. 



8. Sharp, L. W., Spermatogenesis in Equisetum. Box. Gaz. 54:89-119. 

 pis. 7, 8. 1912. 



9* , Spermatogenesis in Marsilia. Box. Gaz. 58 : 419-43 1 . pis. 33, 34. 



1914. 



10. Wilson, M„, Spermatogenesis in the Bryophyta. Ann. Botany 25:415- 



457- pis. 37 j 38. figs. J. 191 1. 



11. Woodburn, W. L., Spermatogenesis in certain Hepaticae. Ann. Botany 

 25:299-313. pi 25. 1911. 



12 - •, Spermatogenesis in Blasia pusilla. Ann. Botany 27:93-101. 



pi. 11. 1913. 



1 3- — ■ — — -, Spermatogenesis in Mnium qffine var. ciliaris (Grev.) C. M. Ann. 

 Botany 29:441-456. pi. 2 1. 1915. 



EXPLANATION OF PLATE XV 



All figures were drawn at the level of the table with the aid of an Abbe 

 camera lucida from cells stained with iron alum-haematoxylin. Examination 

 of the cells was made under a Zeiss 2 mm. apochromatic objective, N.A. 1 . 40, 

 but because of its slightly greater magnifying power a Spencer 2 mm. achro- 

 matic objective was used with an 18 ocular for outlining the drawings. The 

 figures, which have not been reduced in reproduction, show a magnification 

 of 4200 diameters. 



Fig. 1. — Androcyte mother cell (penultimate spermatogenous cell) with 

 two centrosomes. 



Fig. 2. — Prophase of last spermatogenous mitosis; centrosomes at poles 

 of developing spindle. 



Fig. 3. — Metaphase; centrosomes at spindle poles. 



Fig, 4. — Late anaphase; centrosomes present. 



Fig. 5. — Telophase; centrosomes near daughter nuclei. 



Fig. 6.— Late telophase; each cell has one centrosome (blephoraplast). 



Fig. 7.— Androcytes (spermatids) rounded off; blepharoplast slightly 

 elongated in each; dark body near nucleus. 



Fig. 8. — Pair of androcytes with vacuoles in cytoplasm. 



Fig. 9.— Androcyte with dark body (limosphere ?) in addition to blepharo- 

 plast. 



