Figure 5. Parapodia and chaetae. A in Systematics, evolution and phylogeny of Annelida - a morphological perspective

Figure 5. Parapodia and chaetae. A. Eunice pennata (Eunicidae); parapodium comprised of dorsal cirrus (dc), neuropodium (nep), ventral cirrus (vc) and branchia (br); acicula invisible. SEM micrograph. B. Scoloplos armiger (Orbiniidae). Cross section showing parapodium with supportive chaetae and chaetal sac; arrowheads point to sectioned chaetae. TEM micrograph. C. Syllidia armata (Hesionidae); notopodium restricted to dorsal cirrus and acicula (ac). D. Streptosyllis websteri (Syllidae). Aciculae (ac) extending outside parapodial lobe (arraowheads). E. Sphaerodopsis minuta (Sphaerodoridae). Acicula with chaetoblast (chb); arrowheads point to junctional complexes. F. Fabricia stellaris (Sabellidae). Parapodium of thorax with capillaries and uncini. G. Lanice conchilega (Terebellidae). Uncini. - ac = acicula, br = branchia, ch = chaeta, cm = circular muscle, coe = coelom, dc = dorsal cirrus, dlm = dorsal longitudinal muscle, ep = epidermis, dbv = dorsal blood vessel, fc = follicle cell, i = intestine, mv = microvillus, nep = neuropodium, obm = oblique muscle, pm = protractor muscle, rm = retractror muscle, snv = subneural blood vessel, vbv = ventral blood vessel, vc = ventral cirrus, vlm = ventral longitudinal muscle, vnc = ventral nerve cord. C, D, F, G: micrographs from living specimens, slightly squeezed.