106 Proceedings of the Royal Society 
The uterine mucosa opposite these smooth portions of the chorion 
was smooth and free from crypts, except where the isolated patches 
of villi were in apposition with it. Eadiating for about 1 inch 
from the pole of the chorion in the gravid horn were narrow non- 
villous bands of the chorion separated by intermediate villous 
surfaces. These hands corresponded to folds of the mucosa free 
from crypts, which radiated from the orifice of the Fallopian 
tube, and were continuous with the longitudinal folds of mucosa 
in that tube. In the non-gravid horn the chorion was devoid of 
villi for about 5 inches from its free end, and for even a greater 
distance the villi were irregularly scattered so that well-defined 
smooth patches could be traced as far as 10 or 12 inches from the 
pole. On some parts of the chorion pedunculated hydatid dilata- 
tions of the villi, about the size of small peas, were irregularly 
scattered. 
When examined microscopically, the villi were seen to be 
arranged in tufts, which varied in size and in the number of villi. 
Some tufts had not more than two or three villi, but more usually 
numbers were collected together, though occasionally short single 
villi arosefrom the chorion in the intervals between the tufts. The 
villi had as a rule a club-shaped form, but some divided into fili- 
form branches. They were highly vascular, and a beautiful extra- 
villous layer of capillaries was distibuted, as in Orca, beneath the 
free surface of the chorion. 
The free surface ofthe uterine mucosa had, as in Orca, a delicate 
reticulated appearance, and was pitted with multitudes of recesses 
and furrows, which again were subdivided into innumerable crypts. 
In the polar regions of the cornua and in the corpus uteri the 
mucosa was more spongy and succulent than in the greatly dis- 
tended part of the gravid horn, in which the mucosa was obviously 
more stretched, so that the pits and furrows were almost obliterated, 
and the crypts opened on the general plane of the mucosa. In 
their general arrangement, and in the vascularity of their walls, the 
crypts in the Narwhal resembled so closely the corresponding 
structures in Orca, that I need not give a special description. The 
layer of cells which lined them was a well-defined cylindrical 
epithelium, many of the cells of which, however, were so swollen 
that the breadth almost equalled the length. 
