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These inequalities of the uterus, and the numerous placentas in consequence, seem to be designed for the purpose of expanding a greater surface for the terminations of the placental vessels for the purpose of receiving oxygenation from the uterine ones; as the progeny of this class of animals are more completely formed before their nativity, than that of the carnivorous classes, and must thence in the latter weeks of pregnancy require greater oxygenation.
It is by means of this vascular apparatus that the foetus is furnished with nourishment. The fetal and maternal placentas are made up of vascular villi and depressions that are separated only by the thin walls of capillaries, and a layer of epithelial cells. This permits a change of material between the fetal and maternal circulation.
There is no real coalescence of the two placentas at any part of the surface of contact. Hence at birth the foetal placenta alone comes away; the uterine placenta is not torn away with it. The formation of the placenta is very different in the second and higher section of the Placentals, the Deciduata. Here again the whole surface of the chorion is thickly covered with the villi in the beginning.
During lifetime the connection between men and their placentas is never withdrawn." The Khasis, although they cannot explain the meaning of the presence of the placenta at the naming ceremony, and the care with which they remove it and hang it up in a tree, are probably really actuated by the same sentiments as the inhabitants of the Southern Moluccas, i.e. they believe that there is, as Dr.
In cows, and other ruminating animals, the internal surface of the uterus is unequal like hollow cups, which have been called cotyledons; and into these cavities the prominencies of the numerous placentas, with which the fetus of those animals is furnished, are inserted, and strictly adhere; though they may be extracted without effusion of blood.
In some sorts it is large, dry, pithy and hard, extending far into the fruit even to below the center; and sometimes seems to divide into secondary or branch placentas or masses of hard cellular matter, while in other varieties it is small and so soft and juicy as scarcely to be distinguished from the flesh.
Twins and triplets, being quite common, will not be considered here, although there are 2 cases of interest of the latter that deserve citation. Sperling reports 2 instances of triplets; in the first there was 1 placenta and chorion, 2 amnions, and the sex was the same; in the second case, in which the sexes were different, there were 3 placentas, 3 chorions, and 3 amnions.
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