POLYCHiETA FROM NORTH AMERICA. 805 



EXPLANATION OF THE PLATES. 



Plate LXXXVII. 



Fig. 1. Serpula coliimhiana from left side, X i. 



Fig. 2. Crucigera sygoyliora, anterior end from right side, X 3. 



Fig. 3. Crucigera Irregularis, whole animal from right side, X 2. 



Fig. 4. Apomatus timsii. 4a., whole animal from the right side, X 3, d.g., dorsal 

 terminal gland ; 4 b, collar seta, X 300 ; 4 c, bladed sickle-shaped seta 

 from thorax, X 300; 4rf, crumpled anterior abdominal seta, X 300; 



4 e, short posterior abdominal, seta X 300 : 4/, thoracic uncinus, X 300. 

 Fig. 5. Pi'ofula joacifica. 5 a, ventral view, X |; 6 6, thoracic seta, X 300; 



5 0, anterior abdominal seta, embedded up to the dotted line, X 200 ; 

 5(?, short posterior abdominal seta, X 300; 5 e, tip of long posterior 

 abdominal seta, X 300; 5f, abdominal uncinus, X 300. 



Plate LXXXVIII. 



Fig. 6. Chitinopoma greenlandica. 6 a, dorso-lateral view, X 2; 66, collar seta, 

 X 460; 6 c, abdominal seta, X 480; Qd, transverse section through 

 pedicle of operculum, v.s. stem of vesicle, X 55 ; 6 e, transverse section 

 through operculum showing vesicle («) suspended in a loose connective 

 tissue, X 48. 



Fig. 7. Spirorhis vitreus, collar seta, X 220. 



Fig. 8. Spirorhis spirillum. 8 a, tube of discoid variety, X 48; 8 6, tube of 

 ascending variety, X 10 ; 8 <;, collar seta, X 200. 



Fig. 9. Spirorbis pusilloides. 9 a, collar seta, X 460 ; 9 6, large abdominal seta, 

 X 460. 



Fig. 10, Spirorbis ambilateralis. 10 a, collar seta, X 220; 10 6, calcareous plate 

 of operculum, lateral view, X 48 ; 10 e, seta from 3rd thoracic segment, 

 showing fringed sickle-shaped extremitj^; 10 c?, ordinary bladed sickle, 

 from 4th segment (twisted end); 10 e, brush -like abdominal seta, c-e, 

 X 220. 



Plate LXXXIX. 



Fig. 11. Spirorbis racemosus, sp. n. 11 a, collar seta, X 220; 11 6, calcareous plate 

 of operculum, X 48 ; 11 c, seta from 3rd thoracic segment, X 460 ; 

 11 d, dorsal view of whole animal showing stalked, brood-pouch, X 12. 



Fig. 12. Spiro7-bis asperatus, seta from 3rd thoracic fascicle, X 460. 



Fig. 13. Spirorhis validus, collar seta, X 460. 



Fig. 14. Spirorbis medius, sp. n. 14 a, collar seta showing shallow posterior 

 notch, X 460. 14 6, ordinary capillary seta from 1st fascicle, X 460. 

 14>c, calcareous plate of operculum, dorsal view, showing talon and 

 lateral wings, X 16. lid, latero-ventral view of opercular plate, 

 showing flat talon with lateral wing-like projections, X 16. 14 e, ser- 

 rate;! bladed sickle, X 460. 



Fig. 15. Spirorbis langerliansi, collar seta, X 460. 



Fig. 16. Spirorhis morclii. 16 a, collar seta, X 220. 16 6, operculum containing 

 ova, lateral view, X 48. 16 e, narrow seta of 2ud and 3rd fascicles, 

 X 220. 16 d, seta from 3rd fascicle, X 220. 



Proo. Zool. Soc— 1912, No. LIV. 54 



