448 KING. [Vou. XIX. 
a cap over one side of the nucleus, thus appearing very similar 
to the yolk-nuclei which, in many kinds of eggs, originate close 
to the nuclear membrane. 
Knappe states that in Bufo vulgaris about one year old the 
cytoplasm of the cells of Bidder’s organ contains a large, 
rounded, refractive body which is sharply marked off from the 
cytoplasm. He maintains, furthermore, that the nucleus puts 
out processes like pseudopodia which engulf this body; after- 
wards the pseudopodia are slowly withdrawn and the nucleus 
again becomes rounded, while the ball of substance is gradu- 
ally dissolved in the karyoplasm. I have not observed this 
remarkable phenomenon in the cells of Bidder’s organ in Bufo 
lentiginosus. In this species of Bufo, at certain stages in 
the development of Bidder’s organ, the cytoplasm of the cells 
contains many granular yolk-nuclei which are more or less 
rounded in form and sharply defined (Fig. 19), but I have 
never seen anything that would indicate that these masses are 
ever taken into the nucleus. 
The inability of the cells of Bidder’s organ to develop into 
functional eggs has been ascribed by Knappe to the fact that 
these cells are not able to form yolk. A study of the early de- 
velopment of Bidder’s organ in Bufo lentiginosus shows that 
in a great many of the cells the first stages in the formation of 
yolk take place, since yolk-nuclei are formed in a manner 
similar to that which takes place in the ovarian ova (Fig. 19). 
Except in the one case to be described later, I have never found 
the development of yolk in the cells of Bidder’s organ pro- 
gressing beyond the stages shown in Figs. 18-19. Were the 
processes leading to yolk formation independent of nuclear 
action it would seem as if they might continue beyond this 
point, since there is no evidence of cytoplasmic degeneration 
at the stage of Fig. 19. The degenerate condition of the 
nucleus at this time is shown by the arrangement of the nu- 
clear contents and by the fact that the cells are dividing 
amitotically. 
Fig. 26 shows a section of a cell taken from the Bidder’s. 
organ of a young male toad with a body length of 2 cm. In 
