Diagnosis
provided by World Register of Marine Species
[Fide Fiege & Barnich, 2009:157] Body dorsoventrally flattened, short, with up to about 50 segments; dorsum more or less covered by elytra. Sixteen pairs of elytra on segments 2, 4, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 26, 29, 32, and 35. Prostomium with distinct cephalic peaks and three antennae with lateral antennae inserted ventrally to median antenna. Anterior pair of eyes at widest part of prostomium, posterior pair dorsal near hind margin. Parapodia with elongate acicular lobes with both acicula penetrating epidermis; neuropodia with a supra-acicular process. Notochaetae stout with distinct rows of spines and blunt to pointed tip. Neurochaetae more numerous and more slender, with distinct rows of spines distally and bi- and unidentate tips. Remarks. Leucia Malmgren, 1867, is closely related to Harmothoe Kinberg, 1856, the only difference being the number of pairs of elytra, which is 16 for Leucia and 15 for Harmothoe.
