No. 2.] DEVELOPMENT OF BIDDER’S ORGAN. 463 
organ is degenerate in both sexes, its cells have taken on the 
character of the least specialized germ-cells, tne ova. The 
Axolotl is the only known amphibian that reproduces while 
in a larval condition, and its genital organs are similar to 
those of other salamanders. Since it is probable that neotenia 
in this form is a phenomenon of adaptation rather than a 
primitive condition, there is little ground for a belief that the 
amphibians as a class were ever sexually mature in a larval 
state. 
The function of Bidder’s organ is as yet undetermined. 
Since this structure is confined chiefly to the Bufonidae it 
hardly seems as if it could have an important role in the 
development of the sex-cells, as Spengel claims; neither can 
it be considered as a storehouse of reserve material that 15 to 
be used during the hibernation period, since measurements 
made of this body at different times of the year show that it 
loses not more than one-half of its volume during the winter 
months. As a rudimentary ovary Bidder’s organ is appar- 
ently functionless, although further research, possibly by 
experimental means, may determine the part played by this 
body in the life history of the individual. 
LITERATURE. 
1. Brpper, F. H. Vergleichende anatomische und histologische Unter- 
suchungen tiber die mannlichen Geschlechts- und Harnwerkzeuge 
der nackten Amphibien. Dorpat, 1846. 
2. Bourn, M. Histogenése de la glande génitale femelle chez Rana 
temporaria. Arch. de Biol., t. XVII, 19or. 
3. Bourne, A. G. On Certain Abnormalities in the Common Frog 
(Rana temporaria). Quart. Journ. Micr. Sci., Vol. XXIV, 1884. 
4. Buuter, A. Riickbildung der Eifollikel bei Wirbelthieren IT. Morph. 
Jahrb., Bd. XXXI, 1902. 
5. Cerrut1, A. Contribuzione per lo studio dell’ organo di Bidder nei 
Bufonidi I. Prosenza di spermii nell’ organo.: Boll. della Soc. 
di Naturalisti in Napoli, Vol. XVII, 1903. 
6. Cerruti, A. Contribuzione per lo studio dell’ organo di Bidder nei 
Bufonidi II. Di una speciale penetrazione di ovule adiacenti nel 
Bufo vulgaris, Laur. Atti della Reale Accad. della Sci. Fisiche e 
matematiche, Vol. XII, 1905. 
