Placoderm

Placodermal (plak'-o-derm, plak-o-ier'mal). In bii having the skin covered with broad flat plate:-. fish. Placenta and Membranes (Stripped upward). tinct and separate, P. panduriform is, one shaped like a violin. P., Poly cotyledonary, P., Poly cotyledonous, a placenta such as is seen in ruminants, in which the chorionic villi are collected in a number of large separate tufts, the latter dipping into corresponding in the uterine mucosa. P. praevia, a term applied to a placenta when it is fixed to that part of the uterine wall that becomes stretched as labor advances, so that it precedes the advance of the presenting part of the fetus. P., Retained, one not expelled by the uterus after labor. P. sanguinis. See Blood-clot. P., Secondary Discoid. See P., Meta discoid. P. spuria. See Placenta succenturiata. P., Subsidiary, a distinct and separate lobe in addition to the usual placental ma ; such lobes are called Placenta: succenturiata:. P. succenturiata, an acce ory growth to the placenta. When this does not act as true placental ti ue it is termed Placenta spuria. P. tripart it a, an anomaly of the placenta in which there are three portions of that organ. P., Triple, the united placentae of a triple gestation. P., Twin. Synonym of P. duplex. P. uterina, the rough cotyledonous or uterine surface of the placenta derived from the decidua serotina. P., Velamen to us, one in which the cord is inserted between the layers of the fetal membranes, presenting a broad surface of attachment in place of the normal round insertion. P., Villous. See P., Di eminated, P., Zonary, a placenta which occupies a broad band around the chorion; it is found in the Carnivora, Jfyrax, Elepltas, and in the Tiibulidentata among the Edentata. Same as P., Annular. Placental (plasen' -tal).