Crustacean appendages are biramous, but have two sets of antennae, and only the second set are biramous. Many forms of crustacean limbs with various parts— basipodite, coxopodite, endopodite, exopodite, and epipodite—appear. On a trilobite, the main branch was the endopodite, ending in a clawlike podomere. The secondary branch was the exopodite, ending in setae. We don’t know whether all arthropods originally had branched appendages, or whether crustaceans developed them later. If we had biramous limbs, would we now be playing xylophones on the ledges of coral reefs?