Eudoxus of Cnidus
There were two "serpent" constellations in Babylonian astronomy, known as Mušḫuššu and Bašmu. It appears that Mušḫuššu was depicted as a hybrid of a dragon, a lion and a bird, and loosely corresponded to Hydra. Bašmu was a horned serpent (c.f. Ningishzida) and roughly corresponds to the Ὄφις constellation of Eudoxus of Cnidus on which the Ὄφις ("Serpens") of Ptolemy is based.