EREANTIATE POLYCHAETA OF JAPAN. 171 



Hakodate Harbour (Mr. K. Yendo) ; Chepissani in Aniwa Bay, 

 Sakhalin (Prof. I. I.jima). 



Swarming : — This worm swarmed in abundance in Hakodate 

 Harbonr on the niglit of May 11th, 190o, according to Mr. K. 

 Yendo' s observation. 



Nereis oxypocla Marenz. 



PI. XVIII, figs. 8—11. 



1879. Nereis oxj-poda, Mareuzeller. Süd jap. Annel., p. 12, Taf. JI, 

 Fig. 3. 



Body gradually tapers towards posterior end, consisting of 

 224-250 sec^ments. It measures 230-300 mm. in length, 8 mm. in 

 breadth, and 14 mm. in same including parapodia and bristles at 

 about 50th segment. In the living state, the general colour is 

 flesh-red ; but in preserved specimens, it changes into liver- 

 lirown on the dorsum, and whitish on the large foliaceous 

 superior ligula, as was stated by Marenzellee. 



Prostomium in tlie basal region between tentacular cirri, 

 broader than long ; beyond i]w region of anterior eyes it narrows 

 anteriorly. Tentacles about | the length of prostomium, closely 

 set at tlieir base. Palpi large, exceeding the tentacles by their 

 Icnnh-lilcc (MM I -piece. Peristomium about l-J the length of the 

 succeeding st^gment ; longest tentaculnr cirri reaching to 4th 

 segment. 



The Miiteriormost two pairs of parapodia are small, eacli 

 consisting of a superior and an inferior ligula, in addition to 

 two yetal lobes or lips, which in anteriorly placed parapodia 

 re]"treseiit the ventral r;nnns. The remaining parapodia differs 



