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The vascular appendage which connects the fetus with the parent, and is cast off in parturition with the afterbirth.

Of or pertaining to the placenta; having, or characterized by having, a placenta; as, a placental mammal.

A division of Mammalia including those that have a placenta, or all the orders above the marsupials.

Having reference to the placenta; as, the placentary system of classification.

The mode of formation of the placenta in different animals; as, the placentation of mammals.

Belonging to the Aplacentata; without placenta.

Mammals which have no placenta.

Without a placenta, as marsupials and monotremes. -- n.

A primary division of the Mammalia, including the monotremes and marsupials, in which no placenta is formed.

One of the lobes of the placenta in ruminating animals.

The placenta and membranes with which the fetus is connected, and which come away after delivery.

One of the patches of villi found in some forms of placenta.

Having a cotyledon; tufted; as, the cotyledonary placenta of the cow.

The inner layer of the wall of the uterus, which envelops the embryo, forms a part of the placenta, and is discharged with it.

The little stalk that attaches a seed to the placenta.

A general name for all those placental mammals that have a brain with few or no cerebral convolutions, as Rodentia, Insectivora, etc.

a. They differ from ordinary mammals in having the corpus callosum very small, in being implacental, and in having their young born while very immature. The female generally carries the young for some time after birth in an external pouch, or marsupium. Called also Marsupiata.

Discoidal by derivation; -- applied especially to the placenta of man and apes, because it is supposed to have been derived from a diffused placenta.

The group that includes all ordinary or placental mammals; the Placentalia. See Mammalia.

The rudiment of a seed. It grows from a placenta, and consists of a soft nucleus within two delicate coatings. The attached base of the ovule is the hilum, the coatings are united with the nucleus at the chalaza, and their minute orifice is the foramen.