258 Rickett. — Fertilization of Sphaerocarpos . 
* Roze, E. ( 1872 ): De la fecondation chez les cryptogames superieures, et en particular chez les 
Sphaignes. Bull. Soc. Bot. France, xix. 91-103. 
Sax, K. ( 1916 ) : Fertilization in Fritillariapudica. Bull. Torrey Bot. Club, xliii. 505-22. 
-( 1918 ) : The Behavior of the Chromosomes in Fertilization. Genetics, iii. 309-27. 
Sharp, L.'W. ( 1921 ) : An Introduction to Cytology, pp. ix and 452. New York. 
Shaw, W. R. ( 1898 ) : The Fertilization of Onoclea. Ann. Bot., xii. 261-85. 
Strasburger, E. ( 1870 ) : Die Geschlechtsorgane und die Befruchtung bei Marcliantia polymorpha. 
Jahrb. f. wiss. Bot., vii. 409-22. 
--( 1892 ): Schwarmsporen, Gameten, pflanzliche Spermatozoiden und das Wesen 
der Befruchtung. Hist. Beitr., iv. 48-156. 
- ( 1893 )Uber die Wirkungssphare der Kerne und die Zellgrosse. Ibid., v. 97-124. 
Walker, N. ( 1913 ): On Abnormal Cell-fusion in the Archegonium, and on Spermatogenesis in 
Polytrichum. Ann. Bot., xxvii. 115-32. 
Weniger, W. ( 1918 ): Fertilization in Lilium. Bot. Gaz., lxvi. 259-68. 
Wilson, M. (1911) : Spermatogenesis in the Bryophyta. Ann. Bot., xxv. 415 - 57 . 
Woodburn, W. L. (1920) : Preliminary Notes on the Embryology of Reboulia hemisphaerica. 
Bull. Torrey Bot. Club, xlvi. 461-4. 
YamanouCHI, S. ( 1906 ): The Life-history of Polysiphonia violacea. Bot. Gaz., xlii. 401—48. 
- ( 1908 ) : Spermatogenesis, Oogenesis, and Fertilization in Nephrodium. Ibid., xlv. 
145 - 75 * 
EXPLANATION OF FIGURES IN PLATES III AND IV. 
Illustrating Dr. Rickett’s paper on Fertilization of Sphaerocarpos. 
PLATE III. 
All figures were outlined with the aid of a camera lucida, at a magnification of 2,000 diameters. 
Lenses used were Zeiss comp. oc. 12 and Zeiss apochr. obj. 2 mm., N.A. 1-40. The sections were 
7/i in thickness. The upper end of the figure in every case corresponds to the distal end of the egg. 
Fig. 1. Antherozoid shortly after its entrance into the cytoplasm of the egg. Ten minutes 
after flooding. 
Fig. 2. Egg showing the first phase of fertilization. Two hours after flooding. 
Fig. 3. Male nucleus in the cytoplasm of the egg during the second phase. Seven hours after 
flooding. 
Fig. 4. Third phase. Eighteen hours after flooding. 
Fig. 5. Remainder of female nucleus of preceding figure. 
Fig. 6. Female nucleus of egg during the fourth phase. Thirty-eight hours after flooding. 
Fig. 7. Male nucleus during the fourth phase, showing open type of structure. From the egg 
containing the nucleus shown in Fig. 6. 
Fig. 8. Fourth phase. Thirty hours after flooding. 
Fig. 9. Fourth phase, showing the formation of polar caps in the cytoplasm. Forty-four hours 
after flooding. 
Fig. 10. Male nucleus from the egg of Fig. 9 (in adjacent section). 
Fig. 11. Egg during the fourth phase, showing radiating masses of granules replacing the polar 
caps in the cytoplasm. Forty-eight hours after flooding. 
Fig. 12. Very early example of the fifth phase. Fifty-six hours after flooding. 
Fig. 13. Remainder of female nucleus of preceding figure, showing the first indications of spireme 
formation. 
