ERRANTIATE POLYCHAETA OF JAPAN. 149 



Body slender, posteriorly gradually tapering ; segments 95- 

 135. Lengtli 75-109 mm. ; breadth 4.5-5 mm., or 7-8 mm. in- 

 cluding bristles, in the broadest part of body, which lies at about 

 the 40th segment. 



In the living specimens the dorsum is of a bluish black 

 colour in the anterior 15 or 16 segments, while the remaining 

 parts are brownish gray. 



Prostomium slightly longer than broad ; anterior border 

 obtusely conical ; tentacles shorter than -J the length of prostomi- 

 um, separated at base. Palpi stout, about as long as prostomium. 

 Both pairs of eyes in the posterior half of prostomium, the 

 posterior pair lying very close to the hind border of prostomium ; 

 eyes of anterior pair more apart from each other than those of 

 posterior pair. 



Poristomium 1.V times as long as the next following segment ; 

 longest tentacular cirri reaching to 7th or 8tli segment when 

 laid back along the l)ody ; tentacular cirri of the anterior superior 

 pair reaching to ord segment ; those of the ventral pairs about 

 J as long as those of corresponding dorsal pairs. All tentacular 

 cirri biarticulated. 



A typical parapodium is shown in PI. XYl, fig. 3. The two 

 rami distinct. Superior ligula long and conical ; middle ligula 

 similar, l)ut slightly shorter. Ventral ramus broad and short, 

 being only I as long as dorsal ramus, provided with three lips; 

 lX)sterior lip sliortor than anterior lip; the supra -acicular parts of 

 middle li}) exceeding both otlier lips in length. Inferior ligula 

 longer iluin ventral lamus, but shorter than middle hgula ; 

 all tips of th(.^ three ligulae nearly in a straight line. Dorsal 

 cirrus extends sliglitly beyond tip of superior ligula ; ventral 

 cirrus sliort, aljout ?, as long as inferior ligula. Bristles 



