126 
THE VOYAGE OF H.M.S. CHALLENGER. 
Polynoe ocellata, n. sp. (PI. XII. fig. 3 ; PI. XIIa. figs. 18, 19). 
Habitat. — Dredged in considerable numbers as a commensalistic form in tbe tubes 
of Spiochcetopterus challengerice at Station 233a (off Kobe, Japan), May 19, 1875 ; lat. 
34° 38' N., long. 135° 14' E. ; depth, 50 fathoms ; surface temperature, 62°’6 ; sand. The 
species thus follows the habit of Polynoe scolopendrina, Sav., in the tubes of Terehella 
nehulosa in the Outer Hebrides, of Polynoe marphysoe, M‘L, in the tubes of Marphysa 
sanguinea in the Channel Islands, and other forms. 
The species is extremely elongated and narrow, reaching 60 mm. and upward in 
length, while its breadth, inclusive of the bristles, is about 2 '5 mm. 
The body is slightly tapered in front, but more so posteriorly, the tail being 
terminated by two short styles. The general colour of the dorsum is dull yellowish, 
marked with olive. Each segment is more or less barred transversely with dark olive 
bands, those in the middle of the body being divided into two squares by a median line, 
while the narrow anterior and broad posterior bands are interrupted in each segment. 
Ventrally the anterior fifth is pale, thereafter a blackish pigment-spot occurs at the base 
of each foot. 
The head is shielded by the first pair of scales, and its transverse diameter exceeds 
its antero-posterior. On each side of the tentacle the anterior border has an acute peak, 
and the depressed median region behind the tentacle gives the usual bilobed aspect to 
the head. A large rounded eye is situated on each side a little in front of the lateral 
prominence, and a smaller one at the posterior border. The former are much wider 
apart than the latter. Both show a pale central region over the pigment, and this some- 
times becomes elevated as a phlyctsena in the specimens, which are imperfect^ preserved, 
from their position inside the tubes. The tentacle is not so long as the palpi, and tapers 
from the base to the terminal enlargement, which has a filiform process of considerable 
length at the tij). The antennae are shorter than the tentacle and more slender, and 
the terminal enlargement is less marked. The palpi are fairly developed, gradually 
tapered toward the tip, which is abruptly filiform. The tentacular cirri resemble tlie 
tentacle. The dorsal cirri, again, while they show a distinct enlargement below the tip 
anteriorly, soon lose this, and the organs assume a simple filiform character. After the 
twentieth foot the cirri do not extend beyond the tips of the bristles till near the 
posterior end, where they again become a little longer than the tips of the . bristles. 
All the foregoing organs are quite smooth. The ventral cirrus is short and subulate, the 
tip extending a little beyond the bases of the bristles. The ventral papilla is well 
marked, and as the eminence at its base is indicated by a pigment-speck throughout the 
greater part of the body, the arrangement is unusually distinct. 
The number of scales is upwards of fifty pairs. The first scale is nearly colourless 
