450 THE ANNELIDA POLYCHAETA. 



the lower lip are of distinctive form. The uncini have fewer teeth than ohscurior 

 and the same number as orphnius, but are longer and proportionately more 

 slender than in the latter and have a longer doreal edge, as shown in the figures. 



Amphicteis orphnius, sp. nov.^ 

 Plate 76, fig. 3, 4; Plate 77, fig. 1, 2. 



Color in general a nearly uniform dusky brown. A paler median ventral 

 longitudinal line, which is broader and less clearly marked cephalad. Labial 

 portion of peristomium crossed by a dark stripe. Setae dilute golden yellow. 



Length of type 27 mm. Greatest width anteriorly, 4.3 mm., this being in 

 the region of the fourth and fifth somites. Width in the caudal region, 1.5 nun. 

 The caudal division long and slender. Dorsum strongly convex, the venter 

 more weakly so anteriorly, and in caudal region flat. 



Prostomium presenting above a subquadrate plate or elevation which is 

 incised at its middle in front and convex on each side of the incision. This 

 plate with a distinct median longitudinal furrow above. Its posterior margin 

 concave. In front of and beneath this dorsal plate is a lobe triangular in out- 

 line as seen from above, but with the apex truncate. It bears along its antero- 

 dorsal surface two narrow, longitudinal, submedian ridges extending about the 

 end to the mouth region. Tentacles clavately thickened distad. (Plate 76, 

 fig. 3, 4). 



Peristomium extended into a conspicuous lower lip which is moderately 

 convex and has its anterior and lateral margins together forming a subsemi- 

 circular outline. A dark transverse stripe crosses the lip near its middle, behind 

 this the color paler. (Plate 76, fig. 3, 4). 



Seventeen anterior somites bearing fascicles of capillary setae. The setae 

 in the fascicles of the first two somites few and short, on the other somites more 

 numerous and increasing regularly in length caudad to those of the seventeenth 

 somite, which are about 2.2 mm. long. The somites of the anterior region in- 

 crease in length caudad, the last three being decidedly longest. The first four 

 pairs of fascicles arise on each side in a longitudinal furrow or depression, the 

 processes being scarcely evident in the case of the first two pairs, but distinct in 

 the case of the third and fourth. On the succeeding thirteen somites the noto- 

 podia are moderately long, slenderly cylindrical or conicocylindrical. The uncini 



' 6p(t>i'a'ios, dusky. 



