Z22 CLAVPOLE: [VoL. XIV. 
elongation ceases in the middle or near the beginning of the 
first abdominal segment, and the ovary proper begins. This 
is in structure a simple tube, as shown in Fig. 1, in which are 
found many cells grouped round masses of protoplasm that 
differentiate clearly by staining in Lyon’s blue. These cells 
are large and remarkably rich in chromatin of a peculiar 
arrangement. No nuclei are visible in the protoplasmic masses 
in the stages shown in Figs. 1 and 10, but in an earlier stage 
(Fig. 4), when yolk formation has not yet begun at all, a small, 
much-shrunken nucleus is distinctly visible. Caudad of these 
cell clusters lying in the third to the fourth abdominal seg- 
ments is a large group of cells crowded together with indis- 
tinct outlines (Fig. 1, g.e.). This is easily recognizable as the 
germinal epithelium, and lies distinctly separated from the rest 
of the cells in the ovary. There is no definite arrangement of 
cells in this mass excepting a tendency to run in rows, which 
may lie in any direction, longitudinally, transversely, or dorso- 
ventrally. The germinal mass is evidently non-metameric; 
there is no division of it into parts, and the whole is included 
within the third and fourth body segments. Numerous karyo- 
kinetic figures in the mass show that active proliferation is in 
progress. It is among the cells of some of these outer strings 
that the first differentiation is seen. Typically, the germinal 
cells are small and spherical; the cell bodies are very small 
and the nuclei large with the chromosomes regularly arranged 
on the periphery. Fig. 9 shows the first appearance of differ- 
entiation; in a line of cells among the typical round-nucleated 
cells appears one with a smaller, more oval nucleus containing 
smaller chromosomes which are still on the periphery. The 
development of a string of cells such as is shown in Fig. g into 
an egg mass can be followed in Figs. 2, 8, and 9. When the 
stage represented in Fig. 8 is reached the group of cells has 
passed to the outside edge of the germinal epithelial mass and 
is ready to fall freely into the ovary. 
Returning for a more detailed consideration of the cell 
clusters, it is evident, as shown in Figs. 1, 2, 4, and 8, that 
there are many cells associated with that mass of protoplasm 
which contains, in early stages, the small, shrunken egg nucleus 
