PLACENTAL STRUCTURES OF THE TENREC. 287 
sessile’, but is connected with it by a short cord which meets it at right angles. The 
peritoneal capsule of the ovary is large and loose, opening by a small orifice into the 
general cavity of the peritoneum. The ovary itself has, from the small quantity of its 
stroma, the granulated appearance so well marked in the Shrew and Hedgehog. 
2. Maternal and Fetal Structures developed in utero in connewion with the Embryos. 
Owing to the state of preservation in which the specimen was when it came into my 
hands, the maternal and foetal structures in connexion with the chorion had, in every 
case but one, become self-analyzed into three parts. ‘These parts were, first, an area 
of tissue continuous at its periphery with the non-placental uterine mucous membrane ; 
(Pl. L. fig. 3); secondly, a lamina of membrane floating loosely, and, like the utero- 
placental area, perforated centrally by vascular orifices (fig. 2) ; and, thirdly, the placenta 
proper (fig. 1), of a diameter of about half an inch. One ovum only retains its natural 
connexion with the uterine wall; but in several cases the lamina of membrane (fig. 2) 
ordinarily found floating loosely remains attached to its utero-placental area. Of this 
area I will first speak. It is subcircular, and bounded by a slightly raised parapet of 
uterine mucous membrane (vu P, fig. 3), with which an upgrowth of the chorion (cx! 
fig. 1) was continuous in all the ova, and remains so in one instance at present. The 
diameter of each utero-placental space thus bounded being about half an inch, its area 
is divisible into two regions—one, the outer one, being quoit-shaped and surrounding a 
circular central inner region (Ps, fig. 3). The-depth of the outer ring is about half the 
length of the diameter of the entire area; it is clothed with a mucous membrane of 
pulpy appearance and corrugated more or less regularly. In being thicker, and in being 
corrugated, this portion of the utero-placental area contrasts with the mucous coating 
of non-placental portions of the uterus, the mechanical pressure and contact of the 
many foetuses accounting, probably, for the smoother and thinner character of the 
mucous layer in the latter portions of the organ. The central circular portion of each 
utero-placental area is distinguished, by its irregularly perforated and discoloured ap- 
pearance, both from the ring-shaped area immediately surrounding it and from the 
rest of the uterine mucous coat. The membrane covering both regions in each utero- 
placental area is single, and does not admit of being split up into lamine ; but in several 
cases, the lamina (fig. 2), more commonly found floating freely, is left adhering to the 
utero-placental area. This lamina, when free, presents many orifices of blood-vessels, 
centrally ; and its general structure is loose and pulpy. When adherent to the utero- 
placental area, it is by its outer margin that it is attached along the line of demarcation 
between the outer and inner regions of each utero-placental area. In other words, the 
utero-placental mucous membrane seems to split at this line into two laminz, between 
* The ovary of the Sow is somewhat similarly pedunculate (see ‘ Hunterian Catalogue,’ iv. 2782), and so also 
is that of other animals, as the Rat. 
