Note 653 — CANTO XXV.
James Romanes Sibbald translation
Cacus: Dante makes him a Centaur, but Virgil (Æn. viii.) only describes him as half human. The pool was fed with the blood of his human victims. The herd was the spoil Hercules took from Geryon. In the Æneid Cacus defends himself from Hercules by vomiting a fiery smoke; and this doubtless suggested the dragon of the text.