144 The Significance of Sex. [Feb, 
in forming the paranucleus (see A. m. A., xxvi.), the karyosomata segment to form 
the rosette p and fx, where ż is the figure in the first division and gr that of the last. 
The reticulum is again established in gand gx ; the steps following the final division 
are ete in Fig. 81, a, 4, ¢, etc. 
24,a-s. “ Cy ideri” of the egg of Ascaris megalocephala (a-g), from Car- 
aii Cellule, vol. ii., May, 1886. %-s from Van Beneden, A. B., iv.—a is the nu- 
cleus of a young egg having a beaded filament forming a “skein.” There is besides 
a nucleolus which Carnoy calls a “ — -nucleolus” (x). Soon the filament seg- 
ments (4) into eight karyosomata, and then reticulum of the nucleus can be seen 
remaining. -The egg grows, and when mature, ee containing the spermatozoon, the 
preparations for forming the polar globules are made. The poles of the egg become 
marked each by a plasmatic-nucleolus; and the eight karyosomata now take an equa- 
torial pee in two groups (c), which gives to the germinal vesicle the appearance 
o! ing two germinal spots when viewed with moderate powers. The next stage 
soe the reticulum and wall of the germinal vesicle dissolved (which solution ap- 
pears with all nuclei at oe stage). Two groups of fibres now ray down from one 
pole towards the kary ta (d). The other half of the spindle is soon completed 
in a similar manner. “Then from the poles, where is a granular mass called a “ pla- 
teau,” there ray out into the protoplasm, fibres to form primary asters (1). The 
pti may split and so form several secondary plateaux, one of which is shown at 
’, Fig. ¢, for each pole, but its aster is still primary, because a part of its rays enter 
into the nuclear spindle. There may be several of these formed by repeated split- 
ting of the “ plateau.” ees asters (2) are formed when the streamers flow from 
the karyosomata. Tertiary asters (3) are those ponnera” with primary asters, but 
not a part of nuclear ieai while quatenary asters (4) are small asters scattered 
through the yelk, but they may be connected ady any other aster by one or two fila- 
fixed law governs their production, and the utmost variety of combination may be 
found. The system of asters is much more complex in the formation of the second 
pear globule than in the first. Our description of Fig. z is from the second “ cary 
etique figure.” The asters finally fade out until only one plateau with its bilat- 
on spindle is left; this often closes up on itself (/),so that the polar plate looks like 
an equatorial. plate; the karyosomata are thus carried around into a plane at right 
angles to a. old position, ang ead to approach each other. But this mode of dis- 
The last trace of the spindles and asters 
disappears (zg), the plateaux are reduced to ticulum of the plasma 
is restored, | but not as ya ie membrane of the nucleus. Now the reticulum produces 
Pi simple spi al (the tion’’) between the two groups of kary- 
aaasta. aad the tit periphoral one is at off by an equatorial cell-plate, much as 
two 
each, y re eated, so that only two karyosomata a ave leftin 
de cat ton eee eae 
divide by karyokinesis. After the last polar globule has been extruded (4) the two 
_ karyosomata of the female pronucleus segment up into microsomata, and a similar 
eola uate Aled gee aa eE agen 7 shows the two in a stage 
y eoncestration snd. pais 
