PLATE ҮП. 
Sections of Eggs of Cynthia partita; Fertilization and Early Cleavages. 
Fig. 88.— Division of sperm aster ; crescent substance at periphery on posterior side. 
Fig. 89.—Similar to preceding but showing egg nucleus. 
“Figs. 90 and 91.—Sections at right angles to first cleavage plane but oblique to egg axis, showing the 
union of pronuclei; clear and yellow protoplasm and sperm amphiaster in posterior half 
of egg. 
Fig. 92.—Section in the plane of the first cleavage (future median plane) showing the union of the 
germ nuclei, the clear protoplasm and crescent on the posterior side of the egg, and the 
polar bodies above. 
Кір. 93.—Early prophase of the first cleavage, in the plane of the spindle axis. 
Fig. 94 and 95.—Two dispermie eggs; the first showing two sperm nuclei on the posterior side of the 
egg with a single crescent; the second, two sperm nuclei and one egg nucleus, with the 
clear protoplasm and crescent about equally divided, by a tongue of yolk, between the 
two sperm nuclei. 
Fig. 96.—Section in the plane of the first cleavage and transverse to the spindle, showing a cross sec- 
tion of the equatorial plate near the middle of the egg, surrounded by clear protoplasm, 
also the crescent at the posterior border with some of the yellow spherules all around 
the spindle. 
Fig. 97.—Metaphase of the first cleavage; equatorial section at right angles to the кей 
Figs. 98 апа 99.—Early and late anaphases of the first cleavage; sections in equatorial plane. 
Fig. 99.—Constriction of cell body ; chromosomal vesicles at the ends of the nuclear spindle. In both 
figures the daughter centrosomes are ngiting 1 in the equatorial plane and at right 
angles to the first spindle axis. 
Fig. 100.—Telophase of the first cleavage, showing the rotation of nuclei, centrosomes and cytoplasm 
toward the animal pole of the egg. 
Fig. 101.—Equatorial section, prophase of second cleavage; crescent substance at the posterior pole. 
Fig. 102.—Section at right angles to the preceding and through the axis of one of the spindles; nucleus 
and cytoplasm lie above the equator, yolk and crescent below. 
Fig. 103.— Equatorial section showing precocious division of the centrosomes in one of the blastomeres. 
Fig. 104.—Anaphase of second cleavage; equatorial section; chromosomal vesicles at ends of nuclear 
spindles. 
Fig. 105.—Telophase of second cleavage ; equatorial section, showing the bending of the middle of the 
spindle toward the center of the egg, and a large amount of clear cytoplasm and of 
crescent substance in the posterior quadrants. 
Figs. 106 and 107.—Two sections through one and the same egg in the eight-cell stage; the first 
through the anterior blastomeres; the second through the posterior. The cytoplasm is 
most abundant in the cells at the animal pole, the crescent substance in the two posterior- 
vegetal cells, though it is also found around all the nuclei. The polar bodies, which are 
shown in stippled outlines, are not in the plane of either of these sections, but in the 
region between them. 
