Infraclass
Placentalia (Placental mammals)
Neotoma fuscipes. Photo: Peterson B Moose, U.S. Fish and Wildlife Service, no known copyright restrictions (public domain)
Placentalia is one of the three extant subdivisions of the class of animals Mammalia; the other two are Monotremata and Marsupialia. The placentals are partly distinguished from other mammals in that the fetus is carried in the uterus of its mother to a relatively late stage of development. The name is something of a misnomer considering that marsupials also nourish their fetuses via a placenta, though for a relatively briefer period, giving birth to less developed…