Source : Webster's Revised Unabridged Dictionary (1913)

Echidna \E*chid"na\, n. [L., a viper, adder, Gr. ?.]
   1. (Gr. Myth.) A monster, half maid and half serpent.

   2. (Zo["o]l.) A genus of {Monotremata} found in Australia,
      Tasmania, and New Guinea. They are toothless and covered
      with spines; -- called also {porcupine ant-eater}, and
      {Australian ant-eater}.