Waste deposited here. Drowns if submerged. Disappearance of unnecessary parts. Voice produced in syrinx Characteristics of Mammals Living mammals sharply set off from other living vertebrates. Each side of jaw consists of single bone.
Skull articulates with atlas of vertebral column.
Teeth are restricted to margins of jaws. Single, bony nasal opening . Mammary glands present, secreting milk for nourishing young. Large brain , mainly because of development of cerebral hemispheres. Only in Australian region, under virtual isolation from Eutherians, have a wide variety of marsupial mammals persisted.