OF HYOMOSCHUS AQUATIOUS. 455 
the right; but the latter is considerably more capacious than in the 
non-gravid uterus. The corpus uteri communicates by a constricted 
os with a passage which may perhaps be regarded as a cervix, though 
some might look on it as only the specially modified anterior end of 
the vagina. This part of the genital passage is 1{ inch long and very 
much constricted. Its mucous lining is longitudinally folded; and 
the folds are at intervals so projecting as to give the appearance of 
transverse constrictions. The passage and the os are blocked up by a Page 683. 
whitish viscid mucus. Behind the most posterior transverse constric- 
tion the vagina undergoes a considerable dilatation, and the mucous 
lining exhibits faint longitudinal folds. 
The uterine walls are slightly thinner than those of the human 
stomach. The cavity of the two cornua and of the corpus uteri is 
lined by a well-defined mucous membrane, from which the fotal 
chorion can readily be separated. This mucous membrane forms the 
maternal portion of the diffused placenta characteristic of Hyomoschus. 
The mucosa of both cornua is not elevated into folds, except in close 
proximity to the openings of the corresponding Fallopian tubes; and 
the mucous lining of the corpus uteri is longitudinally folded only in 
proximity to the os uteri. The free surface of the mucous membrane, 
both in the cornua and corpus and on both surfaces of the septum 
uteri, is soft and velvety and pitted with multitudes of minute depres- 
sions just visible to the naked eye. These depressions are the crypts 
in which the villi of the chorion are lodged when the chorion is in situ. 
The crypts are distributed with almost equal regularity over the sur- 
face of the mucosa in the several divisions of the uterus; but on the 
more convex part of the impregnated left cornu the mucosa is not 
quite so thick, so that the crypts are shallower, and over a limited 
area the free surface of the mucous membrane is almost, if not quite, 
free from crypts. We did not, however, see any depressed circum- 
scribed smooth areas surrounded by crypts such as one of us has 
described elsewhere* in the Pig and Lemurs, or polygonal areas 
occupied by crypts and bounded by ridges free from crypts, such as 
are to be seen in the gravid uterus of the Mare. In the regular dif- 
fusion of the crypts over the surface of the mucosa, the gravid uterus 
of Hyomoschus much more closely resembled what has been described 
in Orca gladiatort than it did the uterine mucosa of the Pig, Mare, and 
Lemurs. 
We then carefully stripped portions of the mucous membrane off 
the subjacent muscular coat, and soaked them in glycerine for some 
* Turner, Lectures “On the Comparative Anatomy of the Placenta,” Edin- 
burgh, 1876, and “ Transactions of the Royal Society,” London, 1876. 
t+ Turner, “Transactions of the Royal Society, Edinburgh,” 1871. 
