allantoic

The last of these can be dismissed, in consequence of the recent discovery of an allantoic placenta in Perameles.

It was for a long time held that the Marsupials differed from all other mammals in having no allantoic placenta.

It implies on the whole that the Marsupials have sprung from a stock with an allantoic placenta.

More remarkable still is the development of a small allantoic placenta.

As the allantois increases in size and importance, the allantoic vessels are correspondingly developed.