184 
THE VOYAGE OF H.M.S. CHALLENGER. 
but only one {Lamproderma longicirra) from New Britain in tbe collection of the 
“ Gazelle.” Schmarda, again, mentions a single Hesione and six species of Cirrosyllis, 
but the position of some of the latter, as Ehlers truly says, is doubtful. Two species of 
the group are recorded by Kinberg in his voyage, and Marenzeller describes one from 
Southern Japan. 
Many new genera have, within comparatively recent years, been added to the group 
by Claparede, Grube, De Quatrefages, Marion and Bobretzky, and Ehlers. 
Hesione, Savigny. 
Hesione pacijica, n. sp. (PI. XXIX. fig. 2 ; PI. XXXII. fig. 14). 
Habitat. — Dredged at Station 172, July 22, 1874 (off Nukalofa, Tongatabu) ; 
lat. 20° 58' S., long. 175° 9' W.; depth, 18 fathoms; surface temperature, 75°'0; 
sea-bottom, coral mud. 
A species about 23 mm. in length, and (with feet) nearly 4 mm. in breadth at its 
widest region. 
The body is somewhat fusiform in outline, and the cuticle is iridescent throughout. 
The dorsal surface is convex, while the ventral is grooved by a longitudinal furrow. 
The head is bluntly conical in shape, broader posteriorly than in front. Anteriorly 
are two short and somewhat slender tentacles, arising from the front of each lobe, and at 
some distance from each other. Two eyes are situated in the line of a Y on each side, 
the anterior being slightly larger. On the buccal segment a single cirrus occurs on each 
side. Grouped behind this are three pairs of attenuated cirri, the dorsal considerably 
longer than the ventral, and all being filiform and tapering. The proboscis is ouly 
partly protruded, but shows no processes. It ajDpears to be quite smooth on section. 
The first bristled foot bears a long dorsal cirrus (filiform and tapering like those in 
front), a thick setigerous process, and a somewhat long ventral cirrus. The foot 
(PL XXXII. fig. 14) springs from a curious prominence (slightly marked in this case) 
which projects laterally in each segment. This projection forms a kind of raised 
cushion with characteristic vertical wrinkles, and extends from the anterior to the 
posterior margin of each segment. The number of segments hearing bristles is sixteen 
Unfortunately not a single complete bristle could be found. All had been broken and 
the tips lost. The spine, as usual in the genus, is black. The dorsal cirrus springs 
from a conspicuous basal segment, above which the organ appears to be only crenulated, 
till near the tip, where it is distinctly segmented. It may be segmented throughout in 
life. The ventral cirrus is slightly enlarged at the base, which springs directly from the 
ventral edge of the foot. 
