NO. 3667 POLYCHAETES—-BANSE AND HOBSON 33 
wide. Palps and the first pair of gills insert prior to the first setiger. 
Gills, which can be 5-7 mm long anteriorly, occur throughout 
the body but are mostly lost. The anterior setigers (at least 50) are 
crowded; posteriorly, the length of the segments becomes almost one- 
half their width. The setae of the posterior region originate from slight 
ridges which, however, are not nearly so pronounced as in C. setosa 
Malmeren. The anus is dorsal, with a crenulated margin dorsal and a 
ventral semicircular lip. 
Anteriorly, there are about one dozen long capillary setae in each 
ramus, which are only slightly limbate. When bent, their fibers tend 
to separate with the result that the former cutting edges of the setae 
appear to be feathered. In the notopodia, prior to the occurrence of 
acicular spines, these setae gradually are replaced by shorter setae, 
which resemble obliquely broken-off bristles and have a finely drawn 
tip (fig. 7b). In the middle region of the body they are the only cap- 
illary setae present in noto- and neuropodia (two to four per ramus). 
In young animals near the end of the body, they are replaced by or- 
dinary capillary setae. Acicular spines are slightly curved and have 
rounded tips and slight wings (fig. 7c). Ventrally, they occur from the 
eighteenth to thirty-eighth setigers onward (average 26; n=11). 
Dorsally, they begin 30-40 setigers posterior to the ventral spines. 
There are usually five to seven neuropodial, and two to five notopodial 
spines. Posteriorly, notopodial and neuropodial rami are only slightly 
separated laterally, but the spines do not nearly encircle the body. 
A posterior end of 51 setigers (10 mm long, 1.2 mm wide), apparently 
of a maturing female, and collected in May, carries in the last setigers 
dorsally four to five, ventrally five to six spines, with almost the same 
number of the described capillary setae (fig. 7b) between them. The 
setae are restricted to the sides of the body. There are numerous 
polygonal eggs of 50u-60u freely floating in the body cavity, including 
the last setigers. 
The species seems to be a selective deposit feeder. The largest 
particles in the intestines of two specimens from station 5 (mean 
particle size 0.43 mm) are 0.05 mm in diameter; most are below 0.02 
mm in diameter. 
The name refers to the capillary setae of the middle region of the 
body. 
Diaenosis.—A Chaetozone species with ventral and dorsal acicular 
spines starting ventrally from approximately the twenty-sixth (range, 
eighteenth to fortieth) setiger, with slight wings. Short capillary setae, 
which appear to be obliquely broken-off, in the middle region of the 
body. 
DIFFERENTIAL DIAGNOSIS.—For the characterization of the new 
species, it seems questionable how much significance is to be attached 
313-605—68——3, 
