8 U.S. NATIONAL MUSEUM BULLETIN 227 



foliaceous. Proboscis saclike, unarmed (bottom-deposit feeders). Live 

 in mud or sand with tubes of mucus plus sand or mud (figs. 79-81). 



Paraonidae (p. 298) 



5. Proboscis eversible, unarmed, saclike, used in burrowing and feeding (bot- 



tom-deposit feeders). Body divided into 2-3 regions with parapodia 



differing markedly 6 



Proboscis variable, not saclike. Body with parapodia similar along body, 

 at least not divided into distinct regions (except sometimes in sexual 

 epitokous stages and in Goniadidae, which has anterior uniramous and 

 posterior biramous regions) 8 



6. Body divided into 3 regions. Prostomium more or less fused with buccal 



segment, with pair of long, longitudinally-grooved, spioniform tentacular 



palps (deciduous, may be missing) 7 



Body divided into (1) anterior thoracic region with parapodia lateral and 

 (2) posterior abdominal region with both neuropodia and notopodia 

 directed dorsally, with ligulate postsetal lobes. Branchiae dorsal to 

 notopodia, simple (rarely branched), straplike (postsetal lobes and bran- 

 chiae give straggly, slashed aspect to abdominal region). Parapodia 

 biramous. Prostomium subconical, subglobular or spatulate; without 

 appendages; with pair of inconspicuous nuchal organs; without tentacu- 

 lar palps (figs. 74-76) Orbiniidae (p. 276) 



7. Prostomium and fused buccal segment subconical to suboval, with pair of 



nuchal folds. Parapodia subbiramous, with notopodia cylindrical, with 

 internal acicula only, without notosetae (figs. 77, 78). 



Apistobranchidae (p. 295) 



Prostomium elongate-oval, wedged between first 2 setigers. Parapodia 



biramous, with notosetae (except in middle uniramous region) (figs. 82, 83). 



Trocbochaetidae, New Name (p. 308) 



8. Without dorsal scales or elytra 11 



With dorsal scales or elytra on certain segments, more or less covering 



dorsum (elytra may be hidden by dorsal feltage of capillary notosetae in 

 some Aphroditidae) . . superfamily Aphroditoidea 9 



9. With filiform dorsal cirri on non-elytra-bearing segments 10 



Without dorsal cirri (except sometimes on setiger 3) (figs. 10, 11). 



Sigalionidae (p. 45) 



10. First or tentacular segment with numerous setae. Facial tubercle well 



developed. Dorsal feltage more or less concealing elytra (figs. 1, 2). 



Apbroditidae (p. 11) 

 Tentacular segment with setae few or lacking. Facial tubercle poorly de- 

 veloped or lacking. Dorsal feltage lacking (figs. 3-9) . . Polynoidae (p. 15) 



11. Dorsal surface convex, bristly, formed by elongated transverse notopodial 



or dorsal setigerous lobes nearly covering dorsum, with numerous spinelike 



notosetae in transverse rows 12 



Dorsal surface otherwise 13 



12. Neuropodia not sharply set off from notopodia, with numerous simple 



neurosetae (fig. 14) Eupbrosinidae (p. 62) 



Neuropodia cylindrical, sharply set off from notopodia, with 1 or few com- 

 pound hooked neurosetae. Associated with sponges (fig. 15). 



Spintberidae (p. 66) 



13. Body without spherical capsules. Prostomium distinct. Segmentation 



distinct 14 



