Why was the mammal Echidna named after the Mythical being Echidna?

The echidna (Tachyglossus Aculeatus) was named after the Greek monster Echidna, who was half snake (reptile) and half woman (mammal). She was known as the "Mother of all Monsters" as most of the monsters in Greek mythology were said to have mothered by Echidna.

The most obvious reptilian characteristic of the echidna is that it lays eggs. The mammalian characteristics of the echidna is that they are warm-blooded, have fur, produce milk and suckle their young.

An echidna is part of the Monotreme group. The only other animal in that group in the Platypus.

For more information on Echidna the monster, see the related link.