PLATE XVIIa. 
Fig, 1. Setose bristle, from the middle of the superior series of the tenth 
foot oi Nereis patagonica, ..... x 400. 
Fig. 2. A falcate bristle, from the inferior series of the same foot, . . x 530. 
Fig. 3. A setose bristle, from the middle of the superior series of the 
twelfth foot (in water) of Nereis hrasiliensis, . . . x 400. 
Fig. 4. A falcate bristle, from the inferior border of the twelfth foot of 
the same, ....... x 530. 
Fig. 5, Peculiar crenate dorsal bristle of Stauroceg)halus atlanticus, . x 800. 
Figs. 6, 7. Superior and inferior bristles of the ventral division of the 
foot of the foregoing, . . . . . . x 450, 
Fig. 8. One of the slender elongate bristles from the ventral division of the 
foot in the same, ...... x 350. 
Fig. 9. One of the shorter dorsal bristles of Staurocephalus australiensis, . x 250. 
Fig. 10. Ventral bristle of the foregoing, ..... x 250. 
Fig. 11. One of the superior winged bristles (in calcium chloride), from 
the tenth foot of Lumhriconereis pettigrewi, . . . x 250. 
Fig. 12. Bristle, from the middle of the same foot, . . . . x 250. 
Fig. 13. A posterior hook (in profile) of the same form, viewed laterally, . x 400. 
Fig. 14, An antero-posterior view of a smaller hook from the same region, . x 400. 
Fig. 15. Elongated hook, from the tenth foot of a variety of Lumhriconereis 
pettigrewi, . . . . . . . x 250. 
Fig. 16. Profile view of the upper hook, from a foot near the middle of 
the body of Lumhriconereis hifurcata, . . . x 400. 
Fig. 17. One of the third series (jointed hooks), from the anterior third of 
Lumhriconereis japonica, . . . . , x 250. 
Fig, 18. A posterior hook of Lumhriconereis herguelensis, . . . x 400. 
