464 
THE VOYAGE OF H.M.S. CHALLENGER. 
An injured fragment of the anterior end, consisting of the cephalic region and about 
a dozen bristled segments measuring 8 mm. in length, and having a breadth of 2 ‘5 mm., 
or 4 mm. inclusive of the bristles. 
The general form of the anterior region agrees with Lanassa norderishioldi, Malmgren, 
the dorsum being especially rugose and warty in the form procured by the Challenger. 
A prominent papilla lies in front of the base of the first setigerous process, and a 
diminishing series in the following seven or eight interspaces (setigerous). The bristles 
(PI. XXVIIIa. fig. 4) are pale and long, even longer and more slender in proportion 
than in Malmgren’s species. Each has a somewhat straight shaft, with very narrow wings 
at the upper part, this region being followed by a very long, flattened, tapering tip, 
delicately serrated on one edge. A comparison of the tips of the two species is 
diagnostic, the northern form being more distinctly widened beyond the wings, and 
more abruptly tapered. 
The hooks (PI. XXVIIIa. fig. 5) have even a more highly elevated crown than in 
Lecena neo-zealanice, and of course much more than in Lanassa nordensMoldi. The 
crown has at least ten teeth above the great fang. The outlines of the posterior edge 
and heel quite differ from the first mentioned, the basal region is less convex, and the 
curves below the great hook have little resemblance, and cover a longer space, since the 
anterior inferior angle is much more produced. 
The intestine contained a little greyish sandy mud in which a few Diatoms, 
Coccoliths, and fragmentary Eadiolarians occurred. 
The l)od}^-wall agrees in structure with Pista and the previous species, the hypoderm 
having a great ventral projection, and the circular muscular coat l^eing remarkably thick. 
The longitudinal ventral muscles are firmly enclosed by the oblique muscles internally 
and the circular coat externally. The hiatus above the nerve-area has about the same 
transverse diameter as the latter. The longitudinal dorsal muscles are almost con- 
tinuous. The ovaries and numerous ova occur in the perivisceral chamber. 
Lanassa henthaliana, n. sp. (PI. XLVIll. fig. 8 ; PI. XXVIIIa. figs. 6, 7). 
LLahitat . — Dredged at Station 63 (Mid Atlantic, between Bermuda and the 
Azores), June 19, 1873; lat. 35° 29' N., long. 50° -53' W.; depth, 2750 fathoms; 
surface temperature, 71°'0; sea-bottom, red clay. 
A mutilated anterior fragment, about 2 mm. in diameter and 10 mm. in lengtli. 
No tentacles are present. The dorsum shows anteriorly four boldly elevated 
ridges, corresponding with four segments, the three anterior (second, third, and 
fourth somites) having lateral lamellse, the first or largest meeting its fellow 
of the opposite side ventrally, and forming a second suboral papillose ridge or 
