A prolongation of the median part of the anterior carapace margin, which projects forward between and often beyond the eyes. The rostrum can be of various shapes in lobsters it is usually dorsoventrally depressed and often bears teeth. In many species the rostrum is absent or reduced to a single spine or angle (e.g., in Palinuroidea); in most Nephropoidea it is well developed. In Scyllaridae it is hardly noticeable, but for the presence of a tooth (rostral tooth) or tubercle.