546 
PROFESSOR W. TURNER ON THE PLACENTATION OF THE APES. 
layer of decidua serotina intervened between the placenta and the muscular coat of the 
uterus ; and in the Apes the serotina was proportionally thicker than in the human 
female. In both, the serotina can be divided into two strata, the one comparatively 
thin and immediately related to the placenta, the other considerably thicker and in 
relation to the muscular coat of the uterus. The thin stratum is, without question, 
shed along with the placenta during parturition ; whilst the thicker stratum, either 
altogether or in great part, probably remains on the placental area of the uterus. 
One of the most prominent characters of the thicker stratum in Macacus cynomolgus 
was its loose spongy appearance, due to the numerous areolse or loculi which it con- 
tained ; and in the separation of the placenta there can be little doubt that the septa 
between those loculi which lie next to the thinner and proper placental layer are torn 
through. M. Breschet has figured, but not described, in a vertical section through 
the placenta of Cercopithecus sabceus, a series of spaces ; but the small scale to which 
the figure is drawn makes it somewhat difficult to say if these spaces are intended to 
represent spaces within the placenta, or loculi in the serotina similar to those present 
in M. cynomolgus. Dr. Rolleston, in his account of the placenta of Macacus nemes- 
trinus ,+ described numerous loose lamellae as intervening between the placenta and the 
muscular coat of the uterus, the deeper of which had a horizontal direction, whilst 
those nearer the placenta were vertical. I have little doubt that these lamelhe were 
the septa between a system of loculi, similar to those I saw in M. cynomolgus. 
In human uteri at various stages of gestation, the spongy appearance of the stratum 
of the serotina next the muscular coat of the uterus has been described by several 
anatomists. Friedlander, Kundrat and Engelmann, Kolliker and Leopold, 
have all recognised it, and the stratum has been regarded as homologous with the 
spongy layer of the decidua vera. My attention has also been directed to this matter, 
and I shall now describe the more important characters that I have observed. 
In- two human gravid uteri, from the third to the fifth week,| the decidua serotina 
was irregularly sinuous on its free surface, as is so well delineated by M. Coste in his 
figures of this structure in the early stages of pregnancy. It was nearly two-tenths 
of an inch in thickness, and when vertical sections were made through it was seen to 
consist of a more compact superficial, and of a deeper spongy part. The superficial 
compact portion consisted of two strata. The stratum next the ovigerous chamber 
had a folded or laminated appearance, but its minute structure was not well defined. 
It seemed to consist of an indefinite fibrillated material, which did not colour with 
hsematoxylin. Scattered through this material, and somewhat more numerous in the 
more advanced of the two specimens, were a few corpuscles having the size and form 
* Memoir already cited, plates 3 and 4, fig. 5. 
t Memoir already cited, p. 300. 
| For the opportunity of examining one of these specimens, from the Museum of St. George’s Hospital, 
1 am indebted to Hr. Robert J. Lee ; the other, a somewhat more advanced specimen, in the Museum of 
Guy’s Hospital, Drs. Pye-Smitti and Hilton Fagge kindly gave me permission to examine. 
