SABELLIDES AND SERPULIDES 2 15 



CHONE TERES sp. nov. 

 pi. xxx, fig. i ; pi. XXXVH, figs. 16-23. 

 locality. Dutch Harbor, Unalaska Island. 



A very slender species of a uniform yellowish tint, with very short 

 branchiae and very gradually tapered posterior end without ventral 

 groove or sucker. 



In the single specimen preserved in its tube, the segments, about 80, 

 of which 8 belong to the anterior region, are not very clearly defined. 



Branchiae very short, about 12 in each lobe, longer in the right than 

 in the left one, probably due to inequality in contraction, the longer 

 twisted about the shorter, their rachises connected for the greater part 

 of their length by a delicate membrane. They are furnished on their 

 inner surface with numerous very delicate pinnae, which end abruptly, 

 leaving a thin, comparatively short, broad, abruptly tapered, naked, 

 terminal portion. Eyes none. 



Collar very deep, about 2^ times that of the first segment. Above 

 there are several very long delicate filaments, either abnormal pinnae or 

 undeveloped branchiae. There are two short, stout, dorsal tentacles. 



Both dorsal and ventral grooves or furrows clearly defined ; the 

 dorsal one turning abruptly to the right passes between the eighth and 

 ninth (last thoracic and first abdominal) segments diagonally across 

 the latter below, and merges into the ventral one. 



Fascicles of setae in very straight series, as is usual in this genus. 

 Superior fascicle very small, of but a few slender limbate setae (pi. 

 xxxvii, fig. 16) placed on the first segment at the base of the collar 

 and on the succeeding segments above the elongated inferior fascicle of 

 two rows of spatulate setae (fig. 20), which is above and in front, or 

 forward of and somewhat oblique to the short torus having a single 

 row of hooked setae (fig. 21). There are also found in the superior 

 fascicles a few with abruptly bent shafts bayonet setae (fig. 1 8) . On 

 the abdomen the setse are slender, limbate (fig. 17), in an elongated 

 fascicle just in front of and below the very short torus of uncial plates 

 (figs. 22, 23). 



Length about 56 mm. ; branchiae about 8 mm. ; anterior or thoracic 

 region 9 mm. ; breadth 2.5 mm. 



Tube rough, thin, flexible, semitransparent, amber color, more or 

 less tinted with brown, with very little adhering sand. 



Although no mention of figures of odd ' bayonet ' setae have been 

 noticed in descriptions of any of the known species of this genus, they 

 are not regarded of sufficient importance to warrant any change in the 



