Swimmerets meaning

4) the abdominal appendages are constantly divided into an anterior group of three natatory " swimmerets " and a posterior group of three limbs used chiefly in jumping or in burrowing.

14, third abdominal somite, with appendages or " swimmerets."

These are the plate-like swimmerets and opercula of Gigantostraca and Limulus among Arachnids and of Isopod Crustaceans.

The more primitive forms (Entomostraca) are anomomeristic, presenting great variety as to number of somites, form of appendages, and tagmatic grouping; the higher forms (Malacostraca) are nomomeristic, showing in front of the telson twenty somites, of which the six hinder carry swimmerets and the five next in front ambulatory limbs.