Webster's Revised Unabridged Dictionary · 1913

Amphisbana

Amphisbana ({not transcribed}) , noun

[Latin, from Greek {not transcribed}; {not transcribed} on both ends + {not transcribed} to go.]

1.
A fabled serpent with a head at each end, moving either way. — Milton
2.
(Zoology) A genus of harmless lizards, serpentlike in form, without legs, and with both ends so much alike that they appear to have a head at each, and ability to move either way. See Illustration in Appendix.

The Gordius aquaticus, or hairworm, has been called an amphisbaena; but it belongs among the worms.

Also: Amphisbaena