ElUiANTIAïE POLYCHAETA OF JAPAN. 51 



which coloui' changes in alcohol into a straw yellow or a slightly 

 reddish yellow. In a specimen obtained from a muddy shore, the 

 margin of elytra, tlie pear-shaped process upon them, and the 

 tips of dorsal bristles are all tinted black. 



Prostomium (fig. 0) roundly liexagonal, strongly arched, and 

 divided into two lateral halves by a median furrow. Its length is 

 about equal to tlie breadth. The anterior border is deeply notched 

 by tlie insertion of the basal joint of the median tentacle. The 

 nnterior larger eyes are placed in the middle of lateral mar- 

 gins, and the posterior smaller eyes at a little distance from the 

 posterior margin. Median tentacle nearly o times as long as 

 prostomium ; tlie lateral ones about as long as or a little longer 

 tlian same. All these tentacles provided with round-tipped 

 cylindrical papillae of a deep brownish colour. Subtentacles about 

 4 times the length of prostomium, and covered with very short 

 papillae. The dorsal pair of tentacular eirri is about equal in 

 length to the median tentacle, while the ventral pair is somewhat 

 shorter than same. All tentacular cirri are papillatcd like the 

 tentacles themselves. The basal piece of tentacular cirri has one 

 or two bristles. 



Parapodium somewhat longer than half the breadth of the 

 segment to which it belongs ; the dorsal ramus has, on its in- 

 ferioi' horder, a linger-like ])rocess, in which the aciculum is in- 

 serted ; the ventral ramus has, on its superior border, a similar 

 l)r()cess, from which the bristles arise. Dorsal cirri long and 

 siciKJcr, ahiiDst coloiu'less. and papillate<l like the tentacles. 



Elyti'a in l.~) pairs, home on segments 2, 4, 5, 7 



23, -it, '2\), o'2. They arc generally o\al in sha[)e, but the two 

 anteriormost ])airs are small and of a somewhat circular outline. 

 They are as usual inihrieated and cuver f he dorsal surface of the 



