Mammals

Among the features that distinguish mammals from the other amniotes, the reptiles and the birds, are hair, three middle ear bones, mammary glands in females, and a neocortex (a region of the brain). The mammalian brain regulates body temperature and the circulatory system, including the four-chambered heart. The basic body type is a four-legged land-borne animal, but some mammals are adapted for life at sea, in the air, in the trees, or on two legs. The largest group of mammals, the Eutheria, have a placenta which feeds the offspring during pregnancy. Except for the five species of monotremes (egg-laying mammals), all modern mammals give birth to live young. For more information, visit the Wikipedia entry Get back to Synapsida
Marsupials and kin	Placentals and kin
Monotremes and kin	†Tingamarra
†Yingabalanara	†Dryolestids