454 
Woodburn.—Spermatogenesis in 
be kept entirely separate, but there are indications of a certain amount 
of diffusion from one to the other. 
As the blepharoplast and nucleus lengthen to form the mature sperm, 
they fuse more closely and eventually become indistinguishable, forming 
a homogeneous band or cord which in cross-section may be elliptical and 
densely granular or more nearly circular and hollow, showing the structure 
to be, at certain stages of its development, tubular throughout part of 
its length. 
A vesicle, enclosed within the coiled body of the sperm and containing 
cytoplasm and probably some nuclear material, disappears as the sperm 
approaches maturity. The granular substance of the vesicle is apparently 
used up in the process of development, possibly being directly absorbed 
through the inner surface of the main portion of the sperm. 
The mature sperm is long and slender, almost filiform, pointed at both 
ends, with two cilia attached at the forward extremity of the blepharoplast. 
Bibliography. 
1. Allen, Charles E. (’12) : Cell Structure, Growth, and Division in the Antheridia of Poly - 
trichum juniperum , Willd. Archiv fiir Zellforschung, Band viii, Heft i, pp. 121-88. 
2. Black, Caroline A. (’13): The Morphology of Riccia Frostii , Aust. Ann. of Bot., vol. xxvii, 
No. cvii, July, 1913, pp. 511-32. 
3. Ikeno, S. (’03) : Die Spermatogenese von Marchantia polymorpha. Beihefte zum Botanischen 
Centralblatt, Bd. xv, 1903, pp. 65-88. 
4. Mottier, D. M. (’97): Beitrage zur Kenntniss der Kerntheilung in den Pollen-Mutterzellen 
einiger Dikotylen und Monocotylen. Jahrb. f. wiss. Bot., Bd. xxx, 1897, pp. 169-204. 
5. Walker, Norman (’13): On Abnormal Cell-fusion in the Archegonium; and on Spermato¬ 
genesis in Polytrichum. Ann. of Bot., vol. xxvii, No. cv, Jan., 1913, pp. 115-32. 
6. Wilson, Malcolm (’ll): Spermatogenesis in the Bryophyta. Ann. of Bot., vol. xxv, 
No. xcviii, Apr., 1911, pp. 415-57. 
7. Woodburn, William L. (’ll): Spermatogenesis in certain Hepaticae. Ann. of Bot., vol. xxv, 
No. xcviii, Apr., 1911, pp. 299-313. 
-— (T3): Spermatogenesis in Blasia pusilla , L. Ann. of Bot., 
vol. xxvii, No. cv, Jan., 1913, pp. 93-101. 
8 . 
