of Edinburgh, Session 1875-76. 
105 
imperfect septum, which projected from the inferior wall. Owing 
to the great distension of the left cornu, this septum was pushed to 
the right, so that the os uteri opened directly into only the gravid 
horn. The chorion extended from the end of the gravid to that of 
the non-gravid cornu. As it passed through the corpus uteri it 
was somewhat constricted by the projecting septum. In the whole 
length of the non-gravid horn, and at the free end of the gravid 
horn, the chorion was raised into strong longitudinal folds, which 
corresponded in reverse order with a similar series of folds of the 
uterine mucosa radiating from the orifices of the Fallopian tube. 
At the os uteri the mucosa was raised into strong folds, which radi- 
ated into the gravid chorion for a considerable distance, and in some 
parts of their extent projected as much as 3 inches from the general 
plane of the mucosa, though at the os they had not more than one 
half that projection. The chorion in apposition with this part of 
the mucosa was also folded. In the gravid horn opposite the 
foetus, where the expansion both ot chorion and uterus was the 
greatest, the folds were not present. Except in a few localities, to 
be immediately specified, the whole of the extensive surface of the 
chorion was so covered with vascular villi that, to the naked eye at 
least, no non-villous intervals could be recognised. The chorion 
was adherent to the uterine mucosa, so that gentle traction was 
needed to draw them asunder; and, as the one was peeled off 
the other, the villi of the chorion were seen to be drawn out of 
multitudes of crypts opening on the free surface of the mucosa. 
The chorion, which lay opposite the os uteri and the immediately 
surrounding mucous membrane, was for the most part not villous, 
but presented a smooth, feebly vascular appearance, which con- 
trasted strongly with the adjacent villous chorion. This smooth 
spot was irregular in form, measured 6 inches by 4 inches, and 
from it narrow bands of smooth chorion radiated outwards for 
from 2 to 3 inches between the villous covered folds of the chorion. 
It was similar to, but much larger, than the corresponding spot in 
Orca and the Mare. Small isolated patches of villi were scattered 
irregularly over the surface of this smooth spot. The inner surface 
of the chorion at the bare patch was lined by the amnion and not 
by the allantois. Three inches from this large spot a bare patch, 
1 inch by inch, was completely surrounded by villous chorion, 
VOL. IX. 
P 
