EIUIANTIATE POLYCHAETA OF JAPAN. 55 



Dorsal bristles long and translncent, with a notably extended 

 smooth section at tip (fig. 15) ; the serrated region beneath 

 the smooth section comprises abont 10 spiny rows. 



Ventral bristles also translucent, with rather short and broad 

 tip bent simply in a hook-like manner (fig. 10). The serration 

 of the edge is fine. 



Habitat : — Sagami Bay, about 313 fathoms (Mr. K. Aoki) ; "a 

 little south of Yedo, Japan " (St. 232), 345 fathoms (" Challenger "). 



Uarniothoe holothiivicola n. sp. 



PI. VI, figs, 2—7. 



A single specimen discovered on the under surface of a 

 Holothurian collected in the Uraga Channel, on September 28th, 

 1903, depth about 257 fathoms. 



Body consisting of 39 segments, measures 27 mm. in length, 

 3.5 mm. in maximum breadth at about the 10th segment, and 

 9 mm. including the bristles. The general colour, in the alcoholic 

 specimen, is light brownish, the bristles being yellowish brown. 



Prostomium (fig. 2) liroader than long, divided into two lateral 

 halves by n median anterior notch ; the anterior margin of each 

 lobe broadly rounded ; eyes in tw(^ pairs, black, crescent-like in 

 outline ; anterior eyes placed a little in front of the middle of the 

 lateral border; postci'ior eyes close to the postero-lateral corner of 

 prostomium. 



Tentaculni- ceratophoi-es, arising from below the anterior border 

 of ]irost()mlum, ai-e of a somewhat truncate conical form, the, 

 iiKMlian being twice as long as the lateral. Median tentacular style 

 long and slender, abont 2.^ times as long as prostominm ; and lateral 

 tonta<Milar st\-|es sliglitl\- slioi-ter than ])rost(^minni. Subtentacles 



