PEOF. W. TUENEE ON THE PLA CENTATION OE THE LEMUES. 
581 
e. The form and arrangement of the crypts and the distribution of the blood-vessels 
in their walls are so like what I have seen in Orca and in the Narwhal, that it was 
difficult, when the preparations were placed side by side, to distinguish the one from 
the other. 
f. In the Lemurs the glands did not open into the crypts, but on the surface of the 
depressed smooth areas of the mucosa surrounded by the crypts ; in the Pig, the 
Mare, and occasionally in the Narwhal the glands also did not open into the crypts, 
but on intermediate smooth surfaces of the mucosa, — the peculiarity in the Lemurs 
being that the mouths of so many glands were concentrated in one area ; whilst in the 
Pig and Narwhal, so far as I have seen, only a single gland opened in each smooth 
area, and in the Mare the mouths of the glands opened at intervals on the ridges which 
separated the crypt areas from each other. The placenta in the Lemurs, therefore, 
corroborates the conclusions which have been drawn by Professor Ercolani, of Bologna, 
and myself, from the study of various forms of placenta, that the crypts which receive 
the villi are not produced by a dilatation of the glands, but are new structures arising 
during pregnancy from a hypertrophy and folding of the interglandular part of the 
mucous membrane*. 
In further illustration of the arrangement of the utricular glands in the Lemurs, I 
may relate some observations which I made some months ago on the non-gravid uterine 
mucosa in the Slow Lemur ( Nycticebus tardigradus). The mucosa in each cornu was 
elevated into six distinct longitudinal folds. It was as thick as the muscular coat, and 
covered by a well-defined layer of columnar epithelium. In the deeper part of the 
mucosa the glands were seen to branch repeatedly, and the number of tubes was consi- 
derable. In vertical sections through the membrane these tubes were cut across, some 
transversely, others obliquely or longitudinally. From these branched tubes compara- 
tively few gland-ducts proceeded, which ran very obliquely to open on the free surface 
of the mucosa ; so that the paucity of the tubular glands near the free surface of the 
mucosa, as compared with the deeper part of that membrane, was in conformity with 
what I saw in the gravid uterus of Lemur rufipes. In the uteri of the Pig, Mare, Orca , 
and the Narwhal a gland stem or duct is also formed by the junction of several 
branches. 
In the Lemurs, as in other placental mammals, the crypts are without doubt secreting 
organs. The columnar epithelium which lines them has the characters of a secreting 
epithelium, and the compact subepithelial capillary plexus supplies an abundance of 
blood from which the secretion may be formed f. The concentration of the mouths of 
* The evidence on which this conclusion is based is supplied by Prof. Ercolani in a series of Memoirs which 
have appeared in the ‘ Mem. dell’ Accad. delle Scienze di Bologna ’ from 1868 to 1873, and by myself in my 
Lectures on the Comparative Anatomy of the Placenta, before the Eoyal College of Surgeons of England, 
June 1875, 1st series, published at Edinburgh, 1876. 
f The argument in support of the secreting function of the uterine crypts formed during the development of 
the placenta is stated in my lectures before the Eoyal College of Surgeons of England, above referred to. 
