NO. 3 HARTMAN : ORBINIIDAE, APISTOBRANCHIDAE, PARAONIDAE 225 



lateral organ ("Seitenorgane" of Eisig), the small rounded sta- 

 tionary elevation between notopodia and neuropodia, with stiff project- 

 ing hairs, present in some species of some genera in which an interramal 

 cirrus is absent. 



nephridia, the segmentally arranged organs with external pore, 

 located on the posterior side of neuropodial ridges; at maturity partly 

 functioning as gonopores. 



nuchal organs or nuchal slits, the single pair of ciliated, eversible, 

 epithelial pouches or slits at the postlateral margin of the prostomium, 

 homologous with the segmental ciliary organs in more posterior seg- 

 ments. 



parapodia, the biramous lateral outgrowths of the body, consisting 

 of notopodia, which are more or less uniform throughout the body, and 

 neuropodia, which are variously modified. 



peristomium, the first visible segment behind the prostomium, form- 

 ing a complete ring about the oral aperture, without parapodia or setae. 



podial fringe, the serial rows of lobes or papillae located along the 

 margins of postsetal lobes in thoracic neuropodia and notopodia in some 

 species, especially in Orbinia. 



podial lobe or lobes, located along the postsetal ridge in thoracic 

 notopodia and neuropodia in some species and genera; usually conical 

 or elongated, or divided, or simpler than podial fringe. 



postsetal lobe or lobes (called also dorsal and ventral cirrus), the 

 fleshy foliaceous or cirriform prolongation located behind setal fascicles 

 of both notopodia and neuropodia. 



proboscis, the anteriormost part of the pharynx, epithelial and 

 eversible and more or less branched to simple in Orbiniinae or muscular 

 and noneversible in Protoariciinae. 



prostomium, the anterior pointed or rounded lobe preceding the oral 

 aperture, without appendages but sometimes with eyes (especially in 

 juvenile stages) and a pair of nuchal organs at the postlateral margins. 



pseuduncini, or false uncini, the minute, delicate, uncinal spines as- 

 sociated with the glandular organ in species of Phylo. 



segmental ciliary organ ("dorsal organ" of Rullier, "Wimperhugel" 

 of Eisig), the paired, metameric, epithelial mound present in middle or 

 later thoracic segments and continued to the end of the body, located 

 in front of the branchial base near the segmental groove, covered with 

 cilia and retractile; in Naineris the pair widely separated, in others more 

 modified so that they approach and are more or less embedded anchor- 

 like in the body ; innervated like the nuchal organs. 



