EXPI.ANATION OF PI^iVTE XVI. 



Fig, 9. An extreme example of the thorn-like processes on the dorsal setse 

 of Nais variabilis, var. punjahensis. 



,, 10. Needle-seta of a dorsal bundle of Nais varidbilis, var. 'punjahensis. 



,, ri. Abnormal seta from a dorsal bundle of Nais variabilis, var. punjah- 

 ensis. 



,, 12, 13. Two forms of setal sac of Nais variabilis, var. punjahensis. 



,, 14. Anterior end of a specimen of Nais variabilis, var. punjahensis , to 

 show partial detachment of pharyngeal glandular cells from 

 alimentary tube. 



,, 15. Anterior portion of Nais variabilis, var. punjahensis , to show rela- 

 tions of cerebral ganglion and commissures. 



,, 16 — 18, and Plate XVII, figs. 19 — 21. Various stages in the development 

 of genital organs of Nais variabilis, var. punjahensis. 



