It is a well known faet that in Vertebrates generally — leaving 
aside the Teleosts and some other fishes — rudiments of two sets of 
tubes, the Wolffian (mesonephric) duets and the Mullerian duets 
are formed in every embryonie speeimen, without regard to its 
future sex as a male or a female. In the Vertebrata amniota, during 
development and sex-differentiation, the Wolffian duets undergo 
abortion in the females, and the Mullerian duets develop into ovi- 
duets, while in the males the Mullerian duets are obliterated, and 
the Wolffian duets persist as seminal duets. In many eases the 
Wolffian duets seem to disappear eompletely in the females, and 
the Mullerian duets to do the same in the males; but in some 
eases traees of the duets, developing in the opposite sex, are known 
normally to be preserved, viz. among reptiles and mammals (f. 
ex. in $ of many mammals “Gartnerian (or Malpighian) duets,” 
in cT “uterus maseulinus”, ,,sessile hydatide”); and abnormally 
the duets eharaeteristie of the opposite sex may in some speeimens 
develop to sueh an extent, that we are entitled to speak of these spe¬ 
eimens as pseudohermaphroditie. This being the ease among reptiles 
and mammals there seems to be no obvious reason why birds should 
form an exeeption. Nevertheless I have not found reeorded any 
ease of Mullerian duets preserved in undbubtedly ma 1 e birds, 
neither normally as rudimentary remnants, nor abnormally as testi- 
fying pseudohermaphroditismus. In the literature I have only been 
able to deteet the following two eases whieh to a eertain degree 
may be said to point in the one or other direetion. 
The First ease eoneerns the Afriean ostrieh. In C arus and 
Otto: Erlauterungstafeln zur vergleiehenden Anatomie, Heft V, 
1840, Taf. VII, Fig. 3, is represented the eloaea with appertinent 
struetures of Siriithio camelus J'. The explieation of the figure 
runs: “In der gebffneten Kloake zeigen sieh zu beiden Seiten, be- 
sonders deutlieh aber auf der linken (a und a’) spiral-triehterfbr- 
mige Vertiefungen, in welehen sieh die blinden Analoga mit den 
hier beim Weibehen beginnenden Ovidukten nieht verkennen las- 
sen.” The said struetures — two pits of unequal size — are seen 
laterally-to the large seminal papillæ. Possibly these struetures 
may be found normally in male ostriehes; but any rudimentary 
real oviduets, eonneeted with the pits, are neither mentioned nor 
figured. The seeond ease is a domestie fowl deseribed by Brandt 
