Nectochaeta

the bristled, free-swimming larva of polychaetes. Nectochaetae have segmented bodies and thus are metatroch larvae (nonsegmented larvae are called trochophores). For each of the three to 13 larval segments of the body there is a corresponding pair of lateral appendages called parapodia. The parapodia are bristled. When the larva develops into an adult worm, secondary, or postlarval, segments are successively formed from the growth zone that lies at the posterior end of the larva.