In this contribution I analyze the metrical structure of Seneca's anapaests.After a brief introduction, I first develop a theoretical framework, with specialattention to the boundaries of metrical periods. In the next sections, Ichallenge the common practice of subdividing long anapaestic passages intosocalled anapaestic dimeters. I propose a new analysis in which such a subdivisionis not made, yielding a structure that formally resembles the πνιγη ofclassical Greek comedy.