Anomalies in the Genital Organs of Toads. 163 
\ 
number of tadpoles in various stages of development from the time 
of hatching up to metamorphosis. In no case have I found any 
abnormalities in the gonads proper, although in several instances 
Bidder’s organ on one or both sides had been divided as shown in 
Figs. 11 and 14. The large cells resembling rudimentary ova which 
are found singly or in groups in the genital organs of so many 
young toads that have recently completed their metamorphosis must, 
therefore, develop very quickly, presumably just before or during 
the period of metamorphosis. It is highly improbable that these 
cells originate in Bidder’s organ and subsequently migrate into the 
sex-gland, as there is never any opening between these structures 
except in the female toward the end of the second year when the 
entire Bidder’s organ is degenerating. Such cells, moreover, never 
show the slightest evidence of amceboid movement, and in many 
instances the membrane surrounding them is continuous with that 
inclosing the primordial germ-cells themselves. Judging from my 
previous investigations I am strongly inclined to the opinion that 
these cells are primordial germ-cells in which, for some unknown 
reason, the course of development has been changed so that the cells 
increase in size with unusual rapidity and assume the character- 
istics of rudimentary ova. Cells of this kind must, therefore, be 
considered as degenerating cells. ‘Their presence in the sex-gland 
is apparently not harmful to the individual, since none of the 
young toads in which they are found seem to differ in any other 
way from the normal type. In Bufo, with rare exceptions, all cells 
of this character must become absorbed early in the life history of 
the individual. I have never found any of them in the sex-glands 
of toads that were more than three or four months old. 
According to Pfliiger, ’82, there are three kinds of individuals 
to be found among young frogs killed soon after completing their 
metamorphosis: males, females, and hermaphrodites. In the course of 
a few months the hermaphroditic forms become either definite males 
or females, and in few cases only does the hermaphroditie condition 
persist until the individual becomes an adult. During the course 
of a series of investigations on the determination of sex in frogs, 
Hertwig, 06, ’07, has found a number of individuals in which sex 
