KARYOKINESIS AND ITS RELATION TO FERTILIZATION. 279 
EXPLANATION OF PLATE XIV, 
Illustrating Professor Waldeyer’s memoir on ‘“ Karyokinesis.” 
Fig. 1.—Plan of a resting nucleus, showing the so-called chromatic nuclear 
membrane, the nucleoplasm (Kernsaft), the network (Kerngerist) of chromatic 
threads, the net-knots at the points of junction of these threads, and a 
single rounded nucleolus. 
Fic. 2.—Nucleus at the first stage of karyokinesis—the so-called ‘ dense 
skein ” (after Rabl)—viewed from the “pole,” and showing the excentrically 
placed thread-loops (ex. c.) and two central loops (c.) sticking upwards in the 
centre. The angles of the loops are directed towards the “pole,” and the 
limbs towards the ‘‘ antipole;” the primary threads alone are present at this 
stage. 
Fic. 3.—A nucleus at the same stage, seen from the “antipole,” showing 
the limbs of the primary threads. 
Fic. 4.—Plan of a resting nucleus (after Rabl) seen from the side, with 
the “pole” above, and the “‘antipole” below. On the left are shown only 
the primary threads, in the condition in which they appear in the early stages 
of karyokinesis. On the right the two primary threads are united by secon- 
dary threads, which anastomose with one another, and at some of the points 
> a round nucleolus is also seen. 
of junction are seen “ net-knots ;’ 
Fic. 5.—Nucleus at the stage of “loose skein” (after Rabl), showing the 
nuclear spindle, which makes its appearance at the “pole” of the nucleus. 
The thread-loops or chromosomes are now shorter and thicker than in the 
preceding stage, Fig. 2. 
Fic. 6.—Nucleus at the end of the skein or “spirem” stage. The 
chromosomes are now arranged around the equator of the spindle, which has 
shifted its previous position and taken up an axial position. Three of the 
chromosomes are already longitudinally cleft. 
Fic. 7.—A cell and nucleus, the latter being in the “‘monaster” stage. 
The cell substance is differentiated into an outer dark layer, and an inner 
clear area around the nucleus. The nuclear membrane has disappeared. The 
*pole-bodies”’ are shown at each end of the spindle or “ karyaster,” and 
VOL, XXX, PART 3,—NEW SER. T 
