What does amphisbaena mean?
The definition of amphisbaena
Am`phis*bæ”na, n.
Etym: [L., fr. Gr.

1 A fabled serpent with a head at each end, moving either way. Milton.
2 (Zoöl.)
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.

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