The phrase employs a rare and compressed elliptical construction: τὸ συγκλινές (the 'concave' or 'hollowed-out' part) stands as the subject of an implied verb (likely 'is' or 'lies'), while ἐπ' Αἴαντι functions as a prepositional phrase indicating location. The adjective συγκλινές here is used substantively to denote a specific architectural or topographical feature—a concave slope or hollow—without explicit nominalization, a usage characteristic of Aristophanic comic diction where technical or descriptive terms are often stripped to their barest form for rhythmic or metrical effect. The reference to Aias (Ajax) likely alludes to a specific landmark in Athens, possibly the slope near the sanctuary of Ajax or a topographical feature associated with his mythic burial or cult, requiring knowledge of local Athenian geography to visualize the spatial relationship described.