MICROANATOMY

Detailed explanation-1: -The vast majority of mammals give live birth to their young; the platypus lays eggs. Female mammals feed milk to their young through specialized nipples or teats; female platypuses do not have teats and instead simply “sweat” milk to their young.

Detailed explanation-2: -Monotremes are oviparous, and hatchlings, like those of reptiles, are equipped with an egg tooth, which has a basis of dentine and is used to pierce the eggshell (Green, 1930; Hughes and Hall, 1998).

Detailed explanation-3: -The monotremes are a group of highly specialised egg-laying predatory mammals, containing the platypus and echidnas. There are only five living species of monotreme, contained within two families: Family Ornithorhynchidae: the platypus, a single species in a single genus, Ornithorhynchus anatinus.