376 KING. [Vov. XIX. 
left of the aorta are two germ-cells which lie above the level 
of the genital ridge. Such germ-cells must eventually come 
into the germinal area or degenerate, since cells of this char- 
acter are never found outside of the genital ridge in later 
stages of development. I have never found cells with the 
characteristics of germ-cells in the mesoderm or in the ecto- 
derm. 
In a tadpole twelve to fourteen days old there is usually 
found the beginning of a separation of the median genital 
ridge into two ridges symmetrically placed one on each side 
of the middle line (Fig. 5). This division of the genital ridge 
is evidently brought about through the activity of the germ- 
cells, although I have never been able to find any evidence 
of amoeboid movement in these cells. A longitudinal section 
through a tadpole thirteen days old (Fig. 6) shows that, at the 
time the genital ridge is dividing, the germinal area extends 
from about the level of the liver nearly to the posterior end of 
the body-cavity. When the division is completed the anterior 
portion of each genital ridge contains from two to five germ- 
cells (Fig. 7), while the middle and posterior portions rarely 
contain more than one or two germ-cells (Fig. 8). Sections 
through the posterior region of a genital ridge frequently con- 
tain only the peritoneal cells (Fig. 9) which seem to be 
crowding into the germinal area in increasing numbers at this 
time. 
The primordial germ-cells in the sex-gland of a tadpole 
about to undergo metamorphosis are similar to those found 
in the genital ridge at the stage of Fig. 4, except that they 
contain only a small amount of yolk. After the greater 
part of the yolk has been absorbed there is found in the cyto- 
plasm of these cells a small, round, deeply staining, apparently 
homogeneous body which is sometimes, though not invariably, 
surrounded by a clear area (Fig. 8, V). This body, which I 
shall call the vitelline body, divides previous to the cell mitosis 
(Fig. 7, V), and one of these bodies is to be found subse- 
quently in each of the daughter cells. 
In addition to the vitelline body, there is found in the 
