No. 2.] DEVELOPMENT OF BIDDER’S ORGAN. 445 
in close contact with the large ova of Bidder’s organ, but as 
von Wittich (34) states, Bidder’s organ is always clearly 
marked off from the testis; one never passes gradually into 
the other as Knappe and Ognew (24) maintain is the case in 
Bufo vulgaris. The sharp distinction between Bidder’s organ 
and the sex-gland is not maintained in the female of Bufo len- 
tiginosus after the first year, since at about this time the cavity 
of Bidder’s organ becomes continuous with the central cavity 
of the ovary. Knappe asserts that he has found mature 
spermatozoa in the cells of Bidder’s organ that have begun to 
degenerate, and-he believes that these spermatozoa have de- 
veloped from follicle cells that have entered the cytoplasm of 
the ova. Ina recent paper (King, 17) I have shown that the 
structures considered by Knappe as spermatozoa are very 
probably parasites, since the figures which he gives of these 
bodies are very similar to certain stages in the life cycle of a 
sporozoan parasite which infects the cells of Bidder’s organ 
in the American toad, Bufo lentiginosus. 
As the nuclei in the cells of Bidder’s organ emerge from 
synizesis the nuclear contents does not become arranged in a 
manner similar to that found in the nuclei of the ovarian ova 
in early post-synizesis stages. In the great majority of cases 
practically all of the chromatin goes into a continuous spireme 
(Fig. 9), while the greater portion of the plasmosome sub- 
stance is collected into one or two rounded masses which lie 
in the meshes of the spireme or against the nuclear mem- 
brane (Figs. 10, 14). In some few nuclei the plasmosome 
masses have a smooth outline and they color uniformly red 
when preparations are stained with safranin and gentian violet 
(Fig. 14). In such cases it is evident that all of the chroma- 
tin, except that found in the few small karyosomes which are 
scattered about the nucleus, has gone into the spireme. In 
other nuclei a small amount of chromatin remains attached 
to the outer surface of the plasmosomes, giving these bodies a 
slightly irregular outline (Figs. 9, 10). Nucleolar masses of 
this kind correspond in structure to the compound-nucleoli 
found in the ovarian ova, and their subsequent fate is the 
