The large foot has lateral parapodia (fleshy winglike flaps). The sides of the foot have evolved into parapodia, fleshy winglike outgrowths. The short parapodia (fleshy, winglike outgrowths) are fused on their rear end. The shell is partially or completely enfolded by lateral parapodial (=fleshy winglike outgrowths) lobes. It has a thick, shiny white outer lip that suggests a triangular, winglike expansion. Alate is an adjective that refers to wings or winglike structures. The Clionidae use winglike flaps for rhythmical locomotion, as if flying in the sea. The small lateral winglike flaps (parapoda) are used in a slow swimming mode.