and HIPPOCAMPUS (Ἱπποκάμμπή and Ἱππόκαμπος), the mythical sea-horse, which, according to the description of Pausanias (2.1), was a horse, but the part of its body down from the breast was that of a sea monster or fish. The horse appears even in the Homeric poems as the symbol of Poseidon, whose chariot was drawn over the surface of the sea by swift horses. The later poets and artists conceived and represented the horses of Poseidon and other marine divinities as a combination of a horse and a fish. (Hom. Il. 42.24, 29; Eur. Andr. 1012; Verg. G. 4.389; Philostr. Imag . 1.8; Stat. Theb. 2.45; comp. Welcker in the Class. Museum, vol. ii. p. 394.)
A Dictionary of Greek and Roman biography and mythology
Smith, William
A Dictionary of Greek and Roman biography and mythology. William Smith, LLD, ed. 1890