278 ERNEST W. MACBRIDE. 
later stages this protuberance travels back along the line 
marked out for it by the columnar cells. It nowhere comes 
into contact with the Wolffian duct, nor do the cells of the 
latter exhibit the least sign of proliferation, except in one 
point. This is behind the kidney. A representation is given 
of it in fig. 13. But the facts that it appears early, and before 
the front part of the protuberance is formed, and that it is 
strongly developed in young males (of which I have two series 
of sections), seem to show that it is connected with the forma- 
tion of the vesiculaseminalis. Fig. 13 (which is from a female) 
shows, indeed, that a distinction can be clearly drawn between 
the cells from the proliferating Wolffian duct and those forming 
the protuberance. If my supposition as to the meaning of 
these appearances be correct, it will be a new case of a charac- 
teristically male organ being formed in a rudimentary condi- 
tion in the female. The two males I examined gave me the 
impression that in them only the funnel of the oviduct, and a 
small solid rudiment joining the cloaca, extending but a short 
distance forward, are formed, but they were too young to allow 
one to speak with any certainty on the point. 
The lumen of the oviduct appears only in my latest stages, 
viz. in frogs of 15—17 mm. long (figs. 10 and 11). It appears 
here and there in patches, first in front of, and then behind, the 
kidney—sometimes one cell, sometimes two deep beneath the 
surface. In fig. 10 it appears certainly to be bounded towards 
the outside only by peritoneum. Once formed it sinks in, 
and the whole protuberance bearing it enlarges, and the in- 
different tissue constituting the apparent forward prolongation 
of the kidney ali passes in. There is a certain amount of this 
lymphoid tissue also along the edge of the kidney, as may be 
seen from figs. 10 and 11. Finally, the attachment of the 
whole rod of tissue is drawn out into a mesentery. Excessive 
growth and folding are all that are required to bring about the 
adult condition. 
Fig. 14 shows the manner in which the oviduct, whilst still 
solid, joins the cloaca. It is noteworthy that it is separated 
from the Wolffian duct by one or two layers of flattened cells. 
