1887] 5 The Significance of Sex. 141 
simple @onstriction; the segments of the nucleolus are thus separated without a 
spindle,—a mode of division known as “ stenosis.” 
Fic. 110. N ucleus of muscle-fibre of psi of Hydrophilus (Carnoy, p- 240) enter- 
ing into division. The segments of the nuclein filament are seen lying among the 
fibres of the kpindi, which latter have been bas from the ie oem net- 
work, 
PLATE VII. 
- 111, a—&. Nucleus from cells of endoderm of Ccelenterates except (4) which 
„is aGieciermal-—-Pitcaer .m. xii.—a gives the * skein!” reticulum; 4shows the 
in centre; in g the nucleoli have dissolved; in e the polar asters have formed a 
spindle, and the segments have formed a “ rosette” in its equator ; f shows the “ ro- 
sette” broken up into loops by segmentation of outer limbs of the rosette. This is 
the “m 
get in g the “ dyaster.’’ shows the spindle with the loops near the poles and with 
astral et streaming out into the cytoplasm ; 7 shows the constriction of spindle and 
of cell; in 4 we have a true skein-filament that does not form a reticulum. 
The Sarian of the cel] “ plate,” where (as in plants) there is no cell constriction, , 
may be seen in Figs. 124, and s, and modern text-books on botany. 
Fic. 112, a-g. Kayokinesis from epithelium of Salamander—Flemming, A. m. 
A., xviii.—c, d are from testes as seen in living state. Here we see bodies at the 
poles nearly corresponding in number to the segments of the filament. When the 
dyaster is formed they are about twice as numerous, and strongly suggest that they 
are a species of paranucleolus. cf. 9714, 103, etc. In the daughter-nuclei the series 
a, b, is inversely followed, as in z, f, g. - In g the filament is cut across by the knife 
in many of its windings, thus giving us pseudo-nucleoli. 
Fic. 113, a-g. Epithelium of Salamander according to Rabl, M. J., x.—a is a 
schematic side view, and 4 a polar view of a resting nucleus. According to Rabl the 
segments of the filament do not fuse or in any way anastomose in the resting nucleus, 
but simply branch out finer and finer. Then in kinesis the branches are withdrawn, 
and short thickish loops are formed. The spindle is first seen in its entirety at one 
pole, which, as seen in æ and å, is different from the other pole, and then the spindle 
turns at an angle of 90° and forms the usual amphiaster (c, d). When the srt si 
the halves are carried apart at their dend first, and the shorter arms of th 
separated as seen in e. Arriving at the poles th as in we 
to form the figure æ. In g we see a PE REEE from testicular epithetinns of 
Proteus, where the branching does not take place, but the loops are formed of a row of 
microsomata (beaded filament). 
Fic. 114, a—ġ, shows how such a beaded filament splits by each microsoma divid- 
ing in the general plane of the loop. Pfitzner, M. J., vii. 
FIG. 115, a—e. Nucleus from growing point of Tradescantia vir, virgin tca—Strasburger, 
“ Zellbildung u. NRIS Jena, 1880.—The nearly homogeneous protoplasm of 
the nucleus (a) becomes granular; the granules fuse and arrange themselves in rows 
of microsomata (6), poe these rows are cut across (c) in the equator and pushed to- 
wards the poles while undergoing various changes of segmentation back to granules 
again, but a central nucleolus remains undissolved, or rather is built up during the 
process of reconstruction of the daughter-nucleus (d;e). : 
Fic, 116,a—e. Nucleus of Spirogyra majuscula—Strasburger, 1. c.—In a we see the 
view showing it becoming granular. 
aier nuc — with its nacie] bisa oe 
In 
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