456 KING. [Vor. XIX. 
metamorphosis of the tadpole the cells of Bidder’s organ in- 
crease in number very rapidly and, owing to pressure, they 
are often greatly distorted. The central cavity is formed when 
the cells in the interior of Bidder’s organ degenerate; this oc- 
curs when a young toad has attained a body length of about 
2cm. Inthe female, after the first year, the cavity of Bidder’s 
organ opens into the cavity of the ovary, as Knappe has stated 
is the case in Bufo vulgaris, and eventually the outer wall of 
this organ becomes continuous with the epithelial covering of 
the ovary. Bidder’s organ then appears as a small lobe of 
the ovary which is easily distinguished from the other lobes 
as the cells never develop beyond a certain stage. Bidder’s 
organ then gradually decreases in size and finally disappears. 
Although I have several times carefully examined entire 
ovaries of mature females, I have never been able to find any 
traces of this body. 
In the male toad Bidder’s organ varies greatly in size and 
in appearance at different seasons of the year. In the early 
spring this body appears shriveled and it is somewhat irregular 
in shape. Sections of Bidder’s organ taken’ from toads killed 
at the height of the breeding season in April show that at this 
time the organ has a very large central cavity and that it 
contains a considerable number of degenerating ova and only 
a few young eggs. In the early summer large numbers of new 
eggs are formed at the periphery of Bidder’s organ, and this 
body increases considerably in size and becomes more rounded. 
During the latter part of August and in September the large 
cells begin to degenerate in increasing numbers and only a 
very few young ova can be found. 
Ognew states that the development of Bidder’s organ is 
closely associated with the development of the sex-gland. When 
the sex-gland is resting, Bidder’s organ grows and the num- 
ber of cells increases, but from the time that the formation of 
the spermatozoa begins up to the period of sexual activity 
which occurs in April and May, this organ gradually de- 
creases in size. I cannot agree with Ognew that the sex- 
gland is “resting” during the summer months when Bidder’s 
