96 THE ANNELIDA POLYCHAETA. 



it is encircled by setae, as in the case of the notopodium, excepting for a break 

 on the ventral side, while the aciculum is situated at the centre; the neuro- 

 podium bears near its base on the ventral side a short, subcyhndric, distally 

 acuminate cirrus. 



In each notopodium and neuropodium there is a single stout, dark reddish 

 aciculum occupying a central position with its acute tip extending into a slight 

 conical elevation at the surface. The aciculum is obviously longitudinally 

 fibrillate and may show a cross-striation or cross-wrinkling, particularly in the 

 distal region as shown in the figure. (Plate 15, fig. 7). The setae are arranged 

 on each notopodium and neuropodium in a hne that has the form of an elongate 

 eUipse which is commonly narrowly broken at the dorsal end in the notopodia 

 and at the ventral in the neuropodia. The setae are all simple and none of 

 the crochet-type occur. The setae on the anterior side in each case are much 

 finer than the others and are very flexible; each ends in a fine acute tip below 

 which it is covered until toward the base by numerous, closely arranged, trans- 

 verse, toothed ridges or pectinae. (Plate 15, fig. 4). The principal setae are 

 much coarser; each from a stout base narrows continuously distad, the tip being 

 fine, acute, and smooth, while proximad of the tip the seta along one edge is 

 closely set with very fine teeth or hairs. These setae appear on the average to be 

 coarser in the nem*opodium than in the notopodium. (Plate 15, fig. 5, 6). They 

 are densely fibrillate and through wear often are much frayed distally, the 

 breaks occurring naturally in the direction of the fibriUae which may at the end 

 become separated like hairs and give a brush-like appearance. No specially 

 modified setae on particular parapodia were detected, though the much rubbed 

 condition of some prevented complete study. 



The proboscis is fully protruded in the type. It has a length of 3 mm. 

 and a maximum diameter equal to this. Just within the distal margin and about 

 the opening is a closely arranged series of long papillae each of which is distally 

 bifid with each lobe conical, the two lobes in each case lying in the same vertical 

 or radial plane; the papillae at each side are shorter than the dorsal and ventral 

 ones. Along the distal margin and immediately proximad of it are arranged 

 five encircling series of slenderly conical, well-separated papillae; these decrease 

 in length from those of the most distal to those of the most ventral series which 

 are very small. In the type the papillae form twenty-one radial series. The re- 

 maining median and proximal region of the proboscis is wholly smooth. (Plate 

 15, fig. 2). 



Locality. Off Aguja Point, Peru, 20 m. N. W.: Sta. 4654 (lat. 5° 46' S., 



