EREANTIATE POLYCHAETA OF JAPAN. 233 



two and a half times the width, having 9 annuH. Ventral pair 

 of tentacles slightly longer than the dorsal. Palpi not conspicuous. 



A s typical parapodium of the anterior region may be described 

 the 45t]i (fig. 2). It consists of a rather long ventral ramus, 

 divided into an anterior lobe having two slender ligulœ and a 

 posterior slender and shorter lobe, which is situated just opposite 

 a notch in the former. Ventral cirrus large, arising from the 

 middle of the ventral border of parapodium, and extending a 

 little beyond the tip of anterior lobe ; dorsal cirrus long and 

 slender, arising from the base of parapodium, and running at 

 first laterad, then dorsad, and finally curving downwards. Bristles 

 arranged in a fan- shaped vertical series, all compound. 



Toward the anterior body end, the difference in length be- 

 tween the anterior and posterior lobes of parapodium becomes 

 more and more marked ; the ventral cirrus becomes gradually 

 shorter, so that in the 13th parapodium it is slightly shorter than 

 the anterior lobe ; the dorsal cirrus becomes relatively longer. 



The parapodia in the first two segments of the posterior 

 body region are transitional in form ; more posterioly they quickly 

 assume characteristic structure. 



Typical posterior parapodium (the 140th) consists of a dorsal 

 and a ventral ramus, separated by a w^ide interval and each bearing 

 ils pceiihûi- cirrus (Hg. 3). The ventral ramus is essentially as 

 in an anterior parapodium, Init both the anterior and posterior 

 lobes ;ire mucli l)road('r, i]\o latter being sliglitly shorter than the 

 former, wliile the ventral cirrus nearly equals in length that 

 of tlie îiutei'ior 1()])0. The large compound bristles have vertical 

 fan-like ;irraiigement, each having slender, finely serrated blade 

 (fig. ")) ; ill addition to tliese a few small bristles (fig. G) with 

 very sliort blade are present at the upper end of the bristle-fan. 



