osis.
215. Equatorial plate of first maturation division.
216. Same, side view, showing chromosomes double.
217-218. Anaphase of same mitosis.
219. Daughter spermatocytes of second order.
220. Equatorial plate of second maturation mitosis.
221. Anaphase of same.
222. Young spermatid.
223. Equatorial plate of first polar spindle of winter egg.
224. Equatorial plate of polar spindle of parthenogenetic egg.
225. Equatorial plate of segmentation spindle of parthenogenetic egg.
_Sagitta bipunctata._
FIG. 226. Resting spermatogonia.
227. Prophase of spermatogonial mitosis.
228. Last spermatogonial mitosis, metakinesis.
229. Anaphase of same, showing synapsis of chromosomes at pole of
spindle, and element _x_.
230. Resting spermatocyte of first order.
231. Bouquet stage.
232. Later growth stage.
233. Prophase of first maturation mitosis, some of the chromosomes split
longitudinally.
234. Later stage, chromosomes condensing and element _x_ dividing.
235-237. First maturation mitosis.
238. Division of element _x_ between the two maturation divisions.
239. Second maturation mitosis.
240. Anaphase of same, showing the element _x_ more deeply stained than
the chromosomes.
241. Young spermatids; element _x_ still conspicuous.
[Illustration: STEVENS. PLATE VII.
N. M. S. del
APHIS OENOTHERA--SAGITTA BIPUNCTATA.]
End of the Project Gutenberg EBook of Studies in Spermatogenesis (Part 1 of
2), by Nettie Maria Stevens
*** END OF THIS PROJECT GUTENBERG EBOOK STUDIES IN SPERMATOGENESIS (1 OF 2) ***
***** This file should be named 31545.txt or 31545.zip *****
This and all associated files of various formats will be found in:
http://www.gutenberg.org/3/1/5/4/31545/
Produced by Bryan Ness, Josephine Paolucci and the Online
Distributed Proofreading Team at http://www.pgdp.net. (This
file was produced from images generously made available
by The Internet Archive/American Libraries.)
Updated editions will replace the previous one--the old editions
will be renamed.
Creating the works from public domain print editions means that no
one owns a United States copyright in these works, so the Foundation
(and you!) can copy and distribute it in the United States without
permission and without paying copyright royalties. Special rules,
set forth in the General Terms of Use part of this license, apply to
copying and distributing Project Gutenberg-tm electr
|