ἀμφίσβαινα

English (LSJ)

ης, ἡ, (βαίνω) kind of

   A serpent, supposed to go either forwards or backwards, A.Ag.1233, Ar.Fr.18 D.; ἀ. ἀμφίκρηνος, δίστομος, Nic.Th.372, Nonn.D.5.146.    II ἀ. φλέβες veins connecting the breast and generative organs, Pall.in Hp.2.103D.