DEVELOPMENT, OF THE OVIDUCT IN THE FROG. 279 
Summary and Conclusions. 
The principal new points contained in this memoir are as 
follows : 
(1). The fact that the oviduct arises opposite the first and 
not the third nephrostome of the pronephros, (2). The fact 
that the whole of the duct, and not merely the posterior half 
as Hoffmann supposed, arises for connection with a strip of 
modified peritoneum, apparently by proliferation from it, 
and entirely independently of the Wolffian duct. (8). 
The fact that the lumen appears quite close to the peritoneum, 
and in patches. To these ought to be added that an examina- 
tion of the series from which fig. 5 and fig. 10 are taken, leads 
to the conclusion that the formation of the duct along the 
outside of the kidney takes place not regularly from before 
backwards, but more or less simultaneously, often being better 
marked behind than in front. 
The idea which this investigation has suggested to me is, 
that the whole oviduct is in the Frog a production of the 
peritoneum. It is not a little remarkable that Wiedersheim 
has published a paper on the development of the Crocodile and 
Turtle (‘ Uber die Entwickelung des Urinogenitalappartes bei 
Krokodilen and Schildkréten. Anatomischer Anzeiger, 
1890’), in which he says with regard to these animals, “ Der 
Miillersche gang ist nichts anderes als ein Derivat des Colom- 
epithels sowie des subperitoneal Bildungsgewebes.” 
The view which is still taught in text books is that the 
oviduct is to be regarded as a part of the primitive pronepheric 
duct, and its funnel as one of the pronepheric funnels. This 
view is founded on its development in Elasmobranchs, where 
the anterior knob of the segmental duct is, or was, regarded 
as a rudiment of the pronephros, its knob afterwards becoming 
the funnel of the oviduct. Now in only three groups of 
‘animals is a true pronephros known, viz. Marsipobranchs, 
‘Tectibranchs (Ganoids and Teleostei), and Amphibia. To 
these, according to Wiedersheim, must be added Crocodiles, 
