a grammarian of Alexandria who flourished about the middle of the second century. He is believed to have been one of the preceptors of the emperor Elia Verus; at least he is generally identified with the Hephestion described as holding that office by Julius Capitolinus in his Life of Verus. From Suidas we learn that he was a very voluminous writer; but of all his works none have descended to us except a treatise on the Greek Metres (Ερευνητικῶν τρόπων Μέτρων). This work, though neither complete nor perfectly reliable, is important as forming the basis of our knowledge on the subject. It was first printed at Florence in 1526; again by Turnebus at Paris, with Scholia, in 1553; and a third time by Hudson, with the Prolegomena, attributed to Longinus, Oxford, 1710. Later editions are those of Paau, Utrecht, 1726; and Gaisford, Oxford, 1810, with the Chrestomathia of Proclus. This edition was reprinted at Leipzig in 1832.