170 AET. IT. — A. IZUKA ! 



parapodia, but is longer than the latter in posteriorly placed 

 parapodia. 



Bristles in part witli falcate, and in part with long slender 

 setose, end -piece ; superior ligula, with the exception of that of first 

 5 or C) parapodia, a broad heart-shaped flap, arising from entire 

 base of parapodium ; inferior ligula slender and conical, as long 

 as the ventral ramus ; dorsal cirrus short, filiform, arising from the 

 middle of the dorsal border of superior ligula, and not reaching 

 so far as the dorsal ramus ; ventral cirrus shorter than the 

 dorsal, arising from base of parapodium. Anal segment long 

 and conical, with longitudinal furrows ; with two slender anal 

 cirri. 



Proboscis slender. Paragnathi dark : I. 4 or 5 in a group ; 

 II., lY., in irregular curved rows ; III. in many transverse rows ; 

 V. 2 or 3 ; VI. single or represented by a small irregular mass ; 

 YIL, VIII. in irregular transverse rows. Maxillae black, with 

 6 — 8 strong teeth below terminal fang. 



CD Ö 



Epitocous phase : — The change of parapodia in form is slight 

 and takes place very gradually in both sexes. Superior ligula 

 enlarged ; post-setal lip of venti^al ramus thinly expanded ; ventral 

 cirrus elongated, thickened at base, with small wing-like flaps. 

 Anal segment with 2 slender anal cirri, equalling in length to 

 14 — 16 proceeding segments taken together. 



This species comes very close to both Nereis virens Saes 

 (Ehlers : Die Borstenwärmer, p. 559) and Nereis Brandti (Malge.), 

 but differs from both in the number and arrangement of para- 

 gnathi in region I. Further it differs from N. Brandti in same in 

 regions VII. and VIII., and from N, virens in same in region III., 

 as well as in the number of teeth on the edge of maxillae. 



Habitat : — Wakkanai in Prov. Kitami (Mr. H. Watanabe) ; 



