Wiktionary
a. having a head shaped like that of a horse
Usage examples of "hippocephalic".
He spoke of the fear of Shantaks for night-gaunts, and of how the vast hippocephalic birds fly screaming from the black burrows high up on the gaunt grey peaks that divide Inquanok from hateful Leng.
Great polypous horrors slid darkly past, and unseen bat wings beat multitudinous around him, but still he clung to the unwholesome mane of that loathly and hippocephalic scaled bird.
Trapped though he was by fabulous and hippocephalic winged nightmares that pressed around in great unholy circles, Randolph Carter did not lose consciousness.
The slant-eyed man was small, but the great hippocephalic bird was there to see he was obeyed.
Off that vast hippocephalic abomination leaped the doomed and desperate dreamer, and down through endless voids of sentient blackness he fell.