240 
THE VOYAGE OF H.M.S. CHALLENGER. 
conereis fragilis the number of the bristles is greater. Malmgren’s figure ^ seems to be 
peculiar, since he only rejDresents two sets of bristles. The bristles in the present form 
are moderately elongate, and have the usual structure, though they are somewhat 
Fig. 5. — Tlie posterior part 
of the maxUl 0 e separated ; 
enlarged. 
Fig. 6. — Mandibles of the 
same from the ventral sur- 
face ; similarly enlarged. 
shorter than in Lumhriconereis fragilis. The tips of the bristles (PI. XVIIa. fig. 12, 
from the inferior border) in the three inferior groups of the tenth foot are so slender 
that they bend in the solution of calcium chloride. 
At the thirtieth foot (PL XXXVL fig. 9) only two black spines occur, and the tips of 
the second group of bristles are generally much attenuated. The extremities of the inferior 
groups are shortened, and a winged hook occurs in most of them. The fiftieth foot 
has strong winged hooks superiorly, then a pair of slender bristles with short tips, and 
interiorly hooks of a more delicate formation. Posteriorly only hooks are present. The 
stoutest hooks occur superiorly, and they show a considerably larger tooth at the base, 
and a series of smaller serrations superiorly, generally about four (PI. XVIIa. fig. 13, 
representing a newly developed hook, not yet injured by use ; and fig. 14, an antero- 
jdosterior view of a smaller inferior hook). Each hook is guarded by the double wing, 
which, as Claparede^ shows in Lumhriconereis nardonis, may be drawn back like a 
hand. The tail is terminated by two styles, one on each side of the anus. 
An allied form, dredged at the same place, is distinguished from the foregoing by 
the presence in the fourth grou]3 of the tenth foot of a single winged hook (PI. XVIIa. 
fig. 15) with an elongate tip (as in certain European species). Its occurrence indicates a 
somewhat advanced jDosition of these organs, which in the typical species occur only in the 
segments behind the tenth. The hook does not differ in structure from the anterior ones in 
the typical example. The only other feature is a slight increase in the length of the tips of 
the second group of superior bristles in the same region, and the absence of the black spines. 
1 Op. cif., pi. xiv. fig. 83 b. 
2 Ann41. Clietop., Naples, p. 147, pi. ix. fig. 3. 
