104 
PROFESSOR TURNER ON THE PLACENTATION OF THE SLOTHS. 
cations of the umbilical vessels, is towards the observer ; at the left border of the placenta 
two of the lobes cut through in opening into the uterus are seen in section. ch, the non- 
placental area of the chorion, with branches of the umbilical vessels ramifying in it. ch’, 
strip of chorion subdividing the placenta imperfectly into a right and left lateral half. am, 
the amnion, partially dissected off the imner surface of the chorion and placenta. V, 
the so-called vagina, into which the chorion did not extend; at the lower end of the 
vagina is seen the opening of the urethra. Ep, the epitrichium, which has been drawn 
off the body of the foetus, and at the same time everted. The two stocking-like prolon- 
gations next the foetus had invested the hind limbs, the two next the uterus the fore 
limbs. Fragments of the epitrichium, torn through in order to remove it, are represented 
attached to the auricle, eyelid, lips, and nostril. 
Puate V. 
Figure 4. Vertical section through the entire thickness of a placental lobe, from the chorionic to the 
Figure 5. 
Figure 6. 
Figure 7. 
Figure 8. 
Figure 9. 
Figure 10. 
Figure 11. 
Figure 12 
decidual surface, to show the arrangement of the convoluted intraplacental maternal blood- 
vessels, and their relations to the chorionic villi. Ch, chorion. JD s, deciduous serotina, 
somewhat ragged at the free edge, where it has been torn away from the non-deciduous 
serotina. V V, stem of a villus, extending through the entire thickness of the lobe, and 
giving off branches, V’ V’ V’; those to the left are represented in situ, situated between 
and in contact with the convoluted maternal vessels. The chorionic foetal vessels are 
coloured blue, and are shown, some in transverse, others in oblique sections; whilst the 
long axis of others may be seen. The capillary network was only partially injected in 
this preparation. The convoluted maternal blood-sinuses are coloured red. Magnified 
43 diameters. 
Section through a small portion of a placental lobe, magnified 225 diameters. The structure 
of the foetal villi is displayed, with their numerous fusiform and _ irregularly-shaped 
connective-tissue corpuscles. The foetal capillaries, coloured blue, for the most part 
transversely divided, lie close to the periphery of the villi. The maternal sinuses, 
coloured red, contain a proportion of red blood corpuscles, some of which seem to be 
nucleated. At aa slight separation in the act of making the section has taken place 
between a villus and the adjacent maternal blood sinus, so that the independence of the 
wall of the sinus can be readily recognised. 
A similar section, with the fcetal capillary network, however, more distinct. The plane of 
section has so passed through the tissue of a villus as to shave off the peripheral plexus, 
between the meshes of which a subjacent maternal blood sinus may be seen, 
Puate VI. 
A utero-placental vein, dissected out of the substance of a placental lobe, to display the 
origin of its branches. Magnified 43 diameters. 
Another specimen, showing the continuity of a branch, with a convoluted intra-placental 
vessel. 
Anastomosing intra-placental maternal blood sinuses, dissected out of the substance of a 
placental lobe. Magnified 43 diameters. 
A portion of the wall of a maternal blood-sinus, after the addition of acetic acid, displaying 
the endothelial cells. Magnified 223 diameters. 
Non-gravid uterus of Cholcepus Hoffmanni, cut open to show the longitudinal folds of the 
mucous membrane, and the want of any subdivision into body and cervix. Natural size. 
A portion of the mucous membrane of the non-gravid uterus. At the right side of the 
figure the surface of the membrane is shown with the ovoid nuclei of its epithelial layer, 
and at a the mouth of one of the utricular glands. More to the left this layer has been 
removed, and the short simple utricular glands, corkscrew-like arteries, serpentine veins, 
and capillary network are represented lying in the corpusculated connective tissue. Mag- 
nified 320 diameters. 
