442 KING. [ VoL. XIX. 
ing chromatin reticulum in the meshes of which there are 
several nucleoli. The nucleus maintains its rounded form dur- 
ing the later development of the oocyte and it only becomes 
irregular when the cell degenerates. I cannot confirm Knappe’s 
observations that the nucleus of the cells of Bidder’s organ 
sometimes sends out amoeboid processes by which it moves 
about to accelerate the taking up of nourishment. At the 
stage of Fig. 5 the cells are usually collected in cell nests, as 
are the young odcytes in the ovary. All of the cells of a nest 
are in practically the same stage of development, and doubt- 
less all have arisen by the repeated division of one primordial 
germ-cell. During the early stages of its development Bidder’s 
organ has no outer membrane, but shortly before the tadpole 
undergoes its metamorphosis this body becomes surrounded 
by a capsule which is formed by the peritoneal cells in a 
manner similar to that by which the outer ovarian wall is 
formed. 
The development of the young oocytes in Bidder’s organ 
parallels that of the ovarian odcytes. After the stage of Fig. 
5 the cell body and the nucleus enlarge very rapidly and the 
chromatin forms an apparently continuous spireme which 
stains rather faintly (Fig. 6). When the nucleus has attained 
a diameter of about 0.013 mm., the chromatin shows a marked 
increase in its capacity for staining and the spireme, which 
has become much thicker and somewhat jagged in outline, be- 
gins to condense (Fig. 7). This condensation continues until 
practically all the chromatin is collected in the centre of the 
nucleus where it forms a loose mass of fine fibres in which 
are imbedded several nucleoli (Fig. 8). This is the synizesis 
stage in the odcytes of Bidder’s organ. It corresponds ap- 
proximately to the stage in the contraction of the nuclear con- 
tents in the ovarian odcytes shown in Plate II, Fig. 24, since 
the meshwork of fibres is considerably looser and the fibres 
themselves are much coarser than those in the synizesis stage 
of the egg shown in Plate II, Fig. 25. 
Slight as the differences appear between the synizesis stage 
in the ova of Bidder’s organ and that of the ovarian oocytes, 
