38 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 125 
the anterior margin of the first setiger are separated from each other 
by a gap that is as wide as their diameter. The gills of this segment 
arise between the palps and the notopod; on the following segments, 
they insert just above the notopod. Gills are at least 2 mm long and 
are found at least to the seventieth setiger (length of the largest 
anterior fragment, apparently a juvenile). Approximately the first 20 
setigers are widened laterally, but the dorsum is low and not inflated. 
The external borders of the segments are dorsally well visible. In an 
anterior fragment of 65 setigers, 13 mm long, this anterior region is 2 
mm long (of which the achaetous rings contribute 0.4mm) and 0.5mm 
wide. The anterior region is followed by more than 40 setigers, which 
are about as wide as they are long and are separated from each other 
by deep furrows. Sometimes they appear beadlike. Near the fortieth 
setiger, segments are 0.3 mm long and 0.3 mm wide. The parapodia 
arise on the hindmost portion of the segments. The posterior region 
consists of about 30 setigers, which are crowded and laterally widened 
(inflated). A posterior portion is 1.5 mm long. The anus is dorsal. 
In the anterior region, all setae are capillary. Notosetae are half as 
long as the body is wide. By the twentieth to twenty-fifth setiger, the 
setae of both rami become limbate and weakly serrated (fig. 77). The 
neurosetae shorten in the subsequent parapodia, become very broad, 
and are beset with distinct hairs on the cutting edge (fig. 77). The 
serration is just visible under 400, and thus the setae are not as 
strongly serrated as in 7. serratisetis described below (under oil im- 
mersion, the neurosetae of local specimens of 7. multifilis Moore are 
not quite smooth either but do not appear to be hairy). In the forty- 
fifth setiger of an apparently mature male, there are about 20 of these 
setae in each ramus. In the posterior region, neurosetae are narrow 
and limbate again, similar to figure 77. The tube is apparently ephem- 
eral, being made of soft and fairly transparent mucoid material. 
The name refers to the provisional name used by us prior to the 
description. 
Driaenosis.—A Tharyz species with beadlike setigers in the middle 
section of body. Posterior end inflated. Anus dorsal. Very broad 
neurosetae with distinct hairs on cutting edge in the middle section 
of body. 
DIFFERENTIAL DIAGNOSIS.—Among the Tharyx species in Hartman 
(1959, 1965b) but omitting 7. annulosus (see p. 31), and adding 
Tharyz sp. described by Berkeley and Berkeley (1941, from California) 
and YT. serratisetis, new species, the following have serrated (or ap- 
parently so) neurosetae: 7. dorsobranchialis (Kirkegaard), T. ser- 
ratisetis, new species, 7. tesselata Hartman, and the mentioned Tharyx 
sp. Among these, 7. tesselata has an inflated posterior end like 7. 
