PROFESSOR TURNER ON THE PLACENTATION OF THE SLOTHS. 97 
assume from the similarity in structure that he had not observed them in this 
monkey. 
As I could find no record of observations on the utricular glands, even in 
the unimpregnated uterus in the quadrumana, I examined the mucosa of a 
non-gravid spider-monkey, apparently the A‘eles gricescens, preserved in spirit. 
I found numerous short glands, dilated into pouch-like recesses, and containing 
an abundance of epithelium, opening into the uterine cavity by constricted 
mouths. A few which possessed the form of short tubes were interspersed 
amidst these pouch-like glands. In this ape, as in the human female, the 
mucosa was in close relation to the subjacent muscular coat, and was not 
attached to it, as in the sloth and mammals generally, by a lax coat of sub- 
mucous connective tissue. 
I owe to Dr RouueEston the opportunity of examining a slice of the placenta 
of the Macacus nemestrinus in the Oxford University Museum. Both to the 
naked eye and with a simple microscope, a section through the organ showed a 
spongy character similar to that exhibited by the human placenta. The arbor- 
escent arrangement of the villi and the processes of decidua, prolonged from 
the serotina into the interior of the placenta, corresponded to Dr RoLiesron’s 
description. I examined the bud-like offshoots of the villi microscopically ; the 
capillaries, filled with a yellow injection, were arranged, not in loops, but in 
networks. Between these vessels and the periphery of the villus, a relatively 
thick layer of tissue intervened, which seemed to consist of two strata; one 
next the capillaries, which consisted of cells such as ERcoLANI regards as the 
glandular organ, continuous with the serotina; the other, and more external, 
was apparently composed of flattened cells, which, on the supposition of an 
intra-placental circulation of maternal blood and an involution of the utero- 
placental vessels, probably represents the wall of the maternal blood-vessels 
reflected on to the villus. A microscopic examination of the serotina displayed 
numerous large fusiform cells with ovoid nuclei, mingled with which were 
circular or spherical cells possessing granular contents and nuclei often of a 
globular form. The processes of the decidua contained fusiform cells smaller 
than those just described, and a nucleated protoplasm in which a differentiation 
into definite cell forms was not clearly demonstrable. 
The great attention which has been paid by various eminent anatomists to 
the structure of the human placenta, enables one to institute a closer comparison 
between it and that of the sloth than could be done with regard to the quadru- 
mana. In man the lobes are more closely fused together into a single organ, 
though the original sub-division into separate lobes is not unfrequently shown 
by deep fissures extending from the uterine surface deeply into its substance ; 
and in a case described by M. Brescuet® the outer face of the chorion is said to 
* Répertoire Général, p. 3, Paris, 1826, 

