"Anomalocaris" had an unusual disk-like mouth known as oral cone. The oral cone was composed of several plates organized triradially. Three of the plates were quite large. Three to four medium sized plates could be found between each of the large plates, and several small, wrinkled plates between them. Such oral cone is very different to those of a typical hurdiid radiodont like "Peytoia" and "Hurdia", which is smooth and tetraradial. The mouth resembled a pineapple ring with the center replaced by a series of serrated prongs. The mouth could constrict to crush prey, but never completely close; there was always an opening about 5 millimeters in diameter when the mouth was shut; a centimeter in exceptionally large individuals. Two large frontal appendage (up to in length when extended) were positioned in front of the mouth, at the front of the head. As a shared character across radiodonts, "Anomalocaris" also possessed three sclerites on the top and side of its head. The top one known as a head shield, dorsal carapace or H-element. it was shaped like an oval, with a distinct rim on the outer edge. The remaining two lateral sclerites known as P-elements also ovoid, but connected by a bar-like outgrowth. The P-elements were previously misinterpreted as two huge compound eyes.