15 (13) Body wall covered with large papillae. Posterior dorsal crochets with 

 upper tooth shorter and thinner than the lower (Fig. 26). Anterior hair 

 setae short and strongly bent Peloscolex dukei 



Figure 26. — Dorsal crochet. 



15 (13) Body wall surrounded, at least in part, by accumulations of foreign 

 particles; papillae small or absent. Posterior dorsal crochets with 

 subequal teeth (Fig. 27, 28). Hair setae long, straight 16 



Figures 27 and 28. — Dorsal crochets. 



16 (15) Anterior dorsal crochets with at least one distinct intermediate tooth (Fig. 



29) Peloscolex nerthoides 



Figure 29. — Dorsal crochet. 



16 (15) Anterior dorsal crochets without intermediate teeth (Fig. 30) 



Peloscolex apectinatus 



Figure 30. — Dorsal crochet. 



17 (4) Body wall covered, at least in part, by papillae or accumulation of foreign particles, or 



both. Penial setae absent 18 



17 (4) Body wall smooth; if, rarely, some foreign particles surround body, then penial setae 



are present 19 



18 (17) Body wall with large papillae. Dorsal crochets bifid with upper tooth 



reduced or rudimentary or single-pointed, or both (Fig. 31) 



Peloscolex benedeni (in part) 



Figure 31. — Range of form of dorsal crochets. 



18 (17) Two or more anterior segments of body wall without papillae, or body with 

 accumulations of foreign particles on some parts. Dorsal crochets with up- 

 per tooth well developed; never rudimentary or absent (Fig. 32) 



Peloscolex gabriellae 



Figure 32. — Dorsal crochet. 



10 



