DEVELOPMENT OF THE OVIDUCT IN THE FROG. 277 
the opening in the adult with great care, but I have not been 
able to detect any important difference between its position 
and that of the funnel in the stage just described. The abdo- 
minal opening in a fully-developed frog is not situated dorsally 
but at the base of the lung. It is fimbriated, and these 
fimbriz are continued lying in a groove over the ventral 
surface of the liver round the base of the lung. Itis true that 
the orifice appears to be extended more dorso-ventrally and 
less antero-posteriorly than before, but that is all. 
The Duct behind the funnel.—In the stage to which 
figs. 1 and 2 belong we can trace a distinct strip of columnar 
epithelium on the outer border of the kidney, the whole way 
to the cloaca, just as Hoffmann describes (C.p.e., figs. 7 and 9). 
This is really more distinct in sections than appears in the 
figures, owing to its staining properties. It is continu- 
ous in front with the epithelium, from which 
the funnel is formed. In the next stage, viz. that in 
which there is still a slight rudiment of a tail, a good part 
of the groove which forms the oviducal funnel has been 
converted into a canal, which ends in a thickening of the 
peritoneum as before. Continuous with the latter a slight 
protuberance (fig. 8, Md.) may now be traced running back 
along the outer side of a peculiar cord of lymphoid tissue, 
which joins pro- and meso-nephros, and which later extends at 
the expense of both. This protuberance occurs on the line of 
the modified epithelium referred to. The Wolffian duct takes 
no part in the formation; this can be clearly seen from an 
inspection of figs. 7 and 8. The Wolffian duct in front of the 
kidney is now reduced to a cord of brown degenerate cells, 
from which no new development such as Hoffmann describes 
could be expected. This thickening or protuberance above 
described seems to me to originate entirely from the perito- 
neum ; the cells, or rather closely-packed nuclei composing it, 
have the shape of, and stain exactly similarly to, those forming 
the modified strip of columnar epithelium. However, it is 
clearly impossible to speak with absolute certainty on such a 
point as the origin of cells in a compact cellular mass. In 
