Περὶ Ὀρθολραφίας, in three books, treating of ποσότης, ποιότης, and σύνταξις.

Περὶ Συντάξεως Στοιχείων.

Περὶ Παθῶν, on the changes undergone by syllables and letters.

Συμπόδιον, written during a residence at Puteoli.

Περὶ Γάμου καὶ Συμβιώσεως.

Προτάσεις, of which we know something through the Λίσεις Προτάσεων τῶν Ἡρωδιανοῖ, written by the grammarian Orus.

Ὀνοματικά. All the above works have entirely perished. The passages where they are quoted, with the names of some other treatises of less note, will be found in Fabricius (Bibl. Graec. vol. vi. p. 282, &c.).

Ἐπιμερισμοί. This work was devoted to the explanation of difficult, obscure, and doubtful words, and of peculiar forms found in Homer.

Ἡ καθʼ Ὅλου, or Καθολικὴ Προσῳδία (called also Μεγάλη Προσῳδία), in twenty books. This work also was held in great repute by the successors of Herodianus. It seems to have embraced not merely prosody, but most of those subjects now included in the etymological portion of grammar. An abstract of it was made by the grammarian Aristodemus, which, like the original work has perished. Another epitome is extant in a MS. in the Bodleian library (Cod. Barocc. clxxix.), and an index of the subjects of the different books in Cod. Matrit. xxxvii. The treatise Περὶ Τόνων, published under the name of Arcadius, but which was compiled by a later grammarian, Theodosius of Byzantium, seems also to be an extract from the Προσῳδία of Herodianus.

Περὶ Μονήρους Λέξεως, on monosyllabic words.

The names of a few other treatises are enumerated by Fabricius, but it is very likely that many of them were merely portions of greater works. The following fragments (either of distinct treatises or of different portions of his larger works) have also been preserved: