The frequent occurrence of epipodites and gnatho FIG.
The endopodite, when present, is unsegmented or composed of few segments and forms the " palp," and outwardlydirected lobes representing the exopodite and epipodites may also be present.
When present, the branchiae are generally differentiations of parts of the appendages, most often the epipodites, as in the Phyllopoda.
In the primitive Malacostraca the gills were probably, as in the Phyllopoda and in Nebalia, the modified epipodites of the thoracic limbs, and this is the condition found in some Schizopoda.
The podobranchiae are clearly epipodites, or, more correctly, parts of the epipodites, and it is probable that the arthroand pleuro-branchiae are also epipodial in origin and have migrated from the proximal segment of the limbs on to the adjacent body-wall.