An egg protected by a series of membranes: the amnion, which surrounds the embryo with a constant amniotic fluid environment; the allantois, which allows gas diffusion and waste removal; the yolk sac, [..]

n. An egg that can be laid on land due to the presence of a fluid-filled amniotic sac (amnion) that cushions and protects the developing embryo. amniote - n. Any of a group of land-dwelling vertebrate [..]

The egg of reptiles, birds, and mammals. It possesses a series of extraembryonic membranes that help prevent desiccation, store wastes, and promote gas exchange. These adaptations allowed vertebrates to invade terrestrial habitats. amoeboid movement

A shelled, water-retaining egg that enables reptiles, birds, and egg-laying mammals to complete their life cycles on dry land.

a shelled egg, with a large yolk and a number of shell membranes, which retains water and allows reptiles, birds, and egg-laying mammals to reproduce on land. Named for the amnion, the innermost shell [..]