PROFESSOR TURNER ON THE PLACENTATION OF THE SLOTHS. W@ 
non-placental part of the uterus at the junction of the placental and non- 
placental parts of the chorion. When examined microscopically, this layer 
was seen to consist of a very delicate connective tissue, in which ovoid and 
fusiform nucleated corpuscles, many of which were much larger than ordinary 
connective tissue corpuscles, and containing abundant granular matter, were 
imbedded. From its position, relations, and structure, this layer is undoubtedly 
a decidua reflexa, and its line of reflexion from uterus to chorion could be traced 
all around the line of junction of the placental with the non-placental part of 
the chorion. Growing from the non-placental part of the chorion into the 
decidua reflexa, more especially in proximity to the line of reflection, were 
elongated villi, which could not be regarded as aborted, because slender blue- 
injected blood-vessels, derived from the vascular network already described, 
were prolonged into them, and formed capillary networks in their interior. In 
those villi where the injection was complete, the capillaries were as abundant as 
in the placental villi themselves, so that there can I think be little doubt but 
they played a part, along with the cells of the decidua reflexa, in the nutrition 
of the foetus. No utricular glands were recognised in the decidua reflexa. 
I examined the surface of the non-placental part of the uterine mucous 
membrane both with the naked eye and a pocket-lens, and found it smooth, 
except where a longitudinal band, formed of slight folds, extending in the direc- 
tion of the band itself, passed along the middle of the inferior wall. This band 
was directly continuous with the longitudinal band in the so-called vagina, 
already described. Neither with the aid of a simple lens nor with the com- 
pound microscope could I detect the mouths of any utricular glands on the free 
surface of the mucosa. I then examined numerous vertical sections through 
the mucous and submucous coats and adjacent parts of the muscular wall, but 
without seeing a trace of agland. The blood-vessels were well injected ; some, 
though not all, of the veins had a serpentine course; some, though not all, of the 
arteries were twisted in a cork-screw-like spiral, and a network of capillaries 
lay in the mucous membrane, parallel to the plane of its free surface. 
I then proceeded carefully to peel some of the placental lobes from the pla- 
cental area of the uterus. I first tore through the decidua reflexa along its line 
of reflection from the uterus to the placenta, and then found that, as I slowly 
stripped off the lobes, a delicate areolar tissue was torn through, some of which 
remained attached to the uterine wall, whilst a very thin layer adhered to the 
uterine face of the lobes themselves. The readiness with which the separation 
took place was in itself strong evidence that one had here the natural plane of 
separation between placenta and uterus as it takes place at the time of parturi- 
tion, so that there can be no doubt that the layer which remained on the 
placental area of the uterus was the non-deciduous serotina,* whilst that which 
* T adopt here the descriptive terms introduced by Professor RonuEston. 
