Puppy and zonal placenta, canine

A zonary placenta and near-term puppy as viewed from the left-hand side. The placenta is the organ responsible for delivering hormones, oxygen and nutrients from the mother to the fetus. Waste products such as carbon dioxide are transferred back to the mother for disposal. A zonary placenta consists of a belt-shaped band of tissue surrounding the fetus, and is typically found in carnivores. Other animals with this type of placenta include cats and mustelids, a family of carnivores including the weasel, badger, marten and ferret.