Ward. — Nectonema. 



PLATE II. 



Fig. 12. Tangential section, including cuticula of dorsal line with bristles. 1. C. 

 X 180. 



Fig. 13. Cross section of cuticula with bristles attached, only the basal portions 

 of which are represented. At the lower side lies a cross section of a 

 bristle. 4. C. X 400. 



Fig. 14. Cross section of cuticula with scales attached. Apochr. 4 mm. Compens. 

 Oc. 4. X 360. 



Fig. 15. Cross section of scale with cuticula and hypoderm. Apochr. 4 mm. Com- 

 pens. Oc. 12. X 1,050. 



Figs. 16, 17. Cross sections of scale on cuticula to show central canal. Apochr. 

 4 mm. Compens. Oc. 4. X 360. 



Figs. 18, 19. Surface view of scales on cuticula. Apochr. 4 mm. Compens. Oc. 4. 

 X 360. 



Fig. 20. Cross section of cuticula and hypoderm. Ehrlich's hsematoxylin. Apochr. 

 4 mm. Compens. Oc. 8. X 720. 



Fig. 21. Cross section of body wall just latev al to dorsal line to show structure of 

 the muscles. Apochr. 4 mm. Compens. Oc. 8. X 720. 



Fig. 22. Fragment of muscle after maceration in 60 % KOH, and subsequent 

 treatment with potassic acetate. 3. C. X 320. 



Figs. 23-26. Cross sections of body wall from different individuals to show the dif- 

 ferent widths of the contractile and protoplasmic zones in the mus- 

 cular layer. The contractile zone is represented by a dark band, and 

 the protoplasmic by a lighter tint. 1 A. X 52. 



Fig. 27. Tailed nuclei from muscular layer. Mayer's HCl carmine. Apochr. 

 4 mm. Compens. Oc. 8. X 720. 



Figs. 28-30. Portions from protoplasmic zone of muscular layer, showing the for- 

 mation of corpuscles from the free ends of the muscle C?) cells. Gen- 

 tian violet and eosin. Apochr. 4 mm. Compens. Oc. 4. X 375. 



Fig. 28. Portion of cell nearly cut off at x. 



Fig. 29. Portion of cell at x, which stains more deeply and resembles corpuscles 

 [c-p' .) of tiie body cavity. 



Fig. 30. Corpuscles of different sizes completely separated from protoplasmic 

 zone. 



