NO. 3667 POLYCHAETES—BANSE AND HOBSON 39 
secundus, but the middle segments are short, whereas there is a bead- 
like middle section in the new species. 
Tharyx serratisetis, new species 
Fiaurgs 7k, l 
Tharyx sp. I Banse et al. [in press]. 
Types.—Holotype: USNM 36266 (possibly the posterior fragment 
in the vial is of a second individual), from station 3, 47°44’31’’ N, 
122°31’53’’ W (February 1963). Paratypes: USNM 36267 (2) and 
36268 (1), from the same station (February and April 1963). 
There are numerous fragments, in part of mature animals, from 
several stations, with up to about 125 setigers, 2 cm long and 2 mm 
greatest width. The total length is more likely to be 4 cm, and the 
number of setigers may well reach 200. Most specimens come from 
station 3, fewer come from stations 6 and 8, some were found at 
station 7 (in 2 of 35 hauls from the station), where an egg-bearing 
female occurred. 
Description.—The prostomium is conical and can be slightly 
longer than wide. Eyes are not visible. The achaetous region appears 
to consist of three indistinct rings. Palps are lost. Gills are rare on the 
preserved material and not longer than the body is wide; they arise 
just above the notopod. The anterior setigers are very crowded, and 
external borders of segments are not well visible. The dorsum is high. 
Starting from the fifth to tenth setiger, the ventrum is glandular 
through the sixtieth to seventieth setiger in mature specimens, and 
to the forty-fifth in one young, complete animal 2 cm long and 0.5 mm 
at greatest width. In moderately contracted animals, segments be- 
come about three times as long as in the anterior region from about 
the fiftieth to seventy-fifth setiger. From about the one hundred 
twenty-fifth setiger, segments are about five times as long as the 
anterior ones. The middle region of the body is not beadlike. The 
body tapers gradually to the pygidium, which carries a semicircular 
ventral lip with the result that the anus is dorsal. 
Notosetae are long thin capillaries that are one-half to three-fourths 
as long as the body is wide; neurosetae are one-third to one-half as 
long as the notosetae of this region. All these setae are slightly limbate 
and have cutting edges with fine hairs (fig. 7) that are just visible under 
400 magnification. The hairs appear to be outcroppings of the fibers 
that make up the setae. After the seventy-fifth to one-hundredth 
setigers, these thin neurosetae are replaced by flattened serrated setae, 
measuring about 75u from the beginning of the serrated region to the 
tip (fig. 71), and by about a dozen that are twice as long owing to a 
