Any one of the abdominal appendages of a crustacean, especially one of the posterior ones, which are often larger than the rest, and different in structure, and are used chiefly in locomotion. See Illust. of Crustacea, and Stomapoda.
lateral plate, located on either side of the last abdominal segment, useful in backward swimming
The terminal appendage of the body, belonging to the sixth pleonite. It consists of a basal segment, the protopod, and primitively two uniarticulate rami, a larger endopod and a smaller exopod.