120 
THE VOYAGE OF H.M.S. CHALLENGER. 
Polynoe attenuata, n. sp. (PL XV. fig. 2 ; PL XX. fig. 9 ; PL XIa. figs. 8, 9). 
Hahitat. — Found between tide-marks at Sea Point near Cape Town, along with 
Terehella, Sahella, and Sabellaria, and from its great length and general appearance it 
would seem to be a commensalistic form, probably with the first mentioned. 
The length of the single specimen is about 55 mm., and the breadth, including the 
bristles, about 6 ‘5 mm. 
The body is comparatively long and narrow, and the dorsum has a considerable 
amount of blackish pigment (anteriorly arranged in transverse bars) from end to end, the 
region behind the scales being beautifully marked with symmetrical touches. Moreover, 
the three rows (two lateral and a median) of prominent papillae are in connection with 
the pattern, the lateral being pale while the median is dark. The ventral surface is quite 
pale anteriorly, but posteriorly each segment has some dark greyish j)igment over the 
swelling for the ventral papilla, and between the patches of opposite sides is a somewhat 
linear arrangement of pigment-grains. Each segment, moreover, has a long lozenge of 
pigment on each side of the median pale band. 
The head is somewhat dusky, with two eyes of moderate size placed near the posterior 
border a short distance within the margin, and two (of larger size), as in Polynoe scolo- 
pendrina, Sav., and Harmothoe, just below the peaks of the head in front. The tentacle 
arises from a large base, which fills up the space between the peaks. The column is 
comparatively thick, and slightly dilated below the filiform tip. It is brownish and 
freckled with the pale cilia which densely coat its surface and make a strong contrast 
with the same organ in Polynoe scolopendrina. The dilatation and filiform tip are pale. 
The antennae proceed from bases which lie wholly beneath the former ; and both are of 
the same olive-green colour as the tentacular base. The column of each agrees wth that 
of the tentacle, but the enlargement below the tip is barely appreciable. The palpi are 
absent. The tentacular and dorsal cirri are all covered with short, thick clavate cilia, the 
dilated extremities of the latter showing a granular interior. The anterior cirri have a 
slight enlargement below the filiform tip, but throughout the greater part of the body 
they taper from the base upward. The base of the cirrus soon becomes connected with 
the pigment of the dorsum, and posteriorly the same dark grey coloration passes along 
the dorsal aspect of the column." The ventral cirri are short and subulate, and the tips do 
not reach the • bases of the bristles. The ventral papilla is a well-developed cylindrical 
process. 
There are fifteen pairs of scales which meet in the middle line of the dorsum anteriorly. 
The first has a greyish border all round with a whitish spot in the centre. The rest, as a 
rule, present a dark granular inner half, the outer being whitish, with a spot of the same 
blackish pigment. Structurally (PL XX. fig. 9) each is covered with short thick cilia, 
