The 20 cent coin carries a platypus, one of only two egg-laying mammals in the world.

Teinolophos trusleri was a prehistoric species of monotreme, or egg-laying mammal.

The allantois functions similarly in monotremes, which are egg-laying mammals.

It's a little confused about egg-laying mammals--thinks they all look like me.

Three species of egg-laying mammals still exist in Australia and New Guinea.

Funny, I always thought platypuses were the only venomous egg-laying mammals.

Echidnas and the platypus are the only egg-laying mammals, known as monotremes.

Much of the argument is based on monotremes, the egg-laying mammals.

The only other egg-laying mammal is the echidna.

Monotremes, egg-laying mammals, lay soft-shelled eggs similar to those of reptiles.