444 KING. [Vor. XIX. 
cells may in a measure be responsible for the deviations from 
the normal processes which occur during synizesis. On this 
assumption to determine the causes for the rapid growth of 
Bidder’s organ would be to determine also the reason for the 
degeneration of its cells. These causes must be sought through 
experimental work; they cannot be determined from a mor- 
phological study of this body. 
Occasionally, in later development, I have found nuclei in 
the cells of Bidder’s organ which were very much like nuclei 
of ovarian eggs of the same size (Cf. Plate V, Fig. 20 and 
Plate III, Figs. 40-43). In such cases it can only be supposed 
that the nuclear changes which took place during synizesis were 
nearly like those occurring in the ovarian ova and, conse- 
quently, that the cells could continue for a longer time to de- 
velop in a normal manner. 
Stages in the development of the young oocytes of Bidder’s 
organ through the synizesis stage shown in Fig. 8 are to 
be found in young tadpoles in which the sex-glands are still 
in an apparently indifferent state. Soon after the synizesis 
period the cell nests are broken up and the ova, which are 
surrounded by follicle cells, become separated by the connec- 
tive tissue stroma which develops throughout the organ. The 
formation and development of the ova proceeds from the 
periphery centripetally; the oldest and largest cells lie to- 
wards the center of the organ, the youngest cells towards the 
periphery. 
In tadpoles killed at the time of metamorphosis and also 
in young toads one frequently finds at the periphery of Bidder’s 
organ nests of young ova in various stages of synizesis. It 
is doubtless such cell nests that Hoffmann and Cerruti (5) 
have considered as cysts containing sperm-cells, since the cells 
at this time bear but little resemblance to the later stages in 
the development of the ova and they appear somewhat like 
certain stages in the development of the spermatocytes. I 
have never found sperm-cells in the ova of Bidder’s organ. 
Oblique sections passing through the posterior part of this 
organ may show the sperm-cells of the upper part of the testis 
