Read online or download a free book: The Spermatogenesis Of Anasa Tristis
Publisher: General Books LLC (4 Feb. 2012)
By: Frederick Clark Paulmier (Author)
Book format: pdf doc docx mobi djvu epub ibooks (*An electronic version of a printed book that can be read on a computer or handheld device designed specifically for this purpose.)
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1899. Excerpt: ... by my hypothesis, it has seemed worth while to state it, inasmuch as it is the only attempt so far made to explain the difference in number of chromosomes between different species, and it may serve to point the way to a true explanation. A corresponding body has been observed in several other species of Heteroptera, but it has not been studied sufficiently to throw any further light on its meaning. A point which may be of interest is that, judging from the few species examined, the number of chromosomes appears smaller in the higher groups, though this is not without exceptions. VII. General Summary. 1. The blind end of the follicles in the testis of Anasa are filled with isolated spermatogones. After dividing several times, the daughter-cells of each of these become surrounded by a connective-tissue wall, thus forming a cyst, within which all further changes take place. 2. The resting spermatogones are conical, with their apices in the center of the cyst. The round nucleus is at the broad end of the cell and contains the chromatin in the form of a fine network, two hazy masses, and a nucleolus. At the apex of the cell are the remains of the intermediate spindle fibers of the preceding mitotic division. Close to the nuclear membrane and surrounded by an idiozom is a minute centrosome. 3. In preparation for division the chromatin is arranged in a segmented spireme which splits longitudinally. The nucleolus and nuclear membrane disappear and mantle fibers are formed from the linin network of the nucleus. The chromosomes (22 in number) are drawn into an equatorial plate which is at right angles to the long axis of the celI. Of these chromosomes, two are much smaller than the others and have a different history. They are formed from ' the hazy masses of chro...
*Report a Broken Link
Modeling With Mathematics: A Bridge to Algebra II Annotated Teacher's Edition How to Get Back Your Pre-Pregnancy Glory: Valuable Tips for Shedding Off the Baby Weight