Zool. [ad. mod.L. epistoma, f. Gr. ἐπί upon + στόμα mouth.] An appendage in front of the mouth in Crustacea and certain insects.
1852. Dana, Crust., I. 25. The base of the antennæ is thus cut off from the rest of the epistome.
1878. Bell, trans. Gegenbaur’s Comp. Anat., 160. The mouth … is in one division … overhung by a movable process—the epistom.
