224 
THE VOYAGE OF H.M.S. CHALLENGER. 
Head longer than broad ; tentacles fully as long. Eyes of moderate size, devoid of 
lenses. Tentacular cirri much develoj)ed, tlie longest reaching the seventeenth foot. 
Paragnathi — I. and II. absent ; III. present about five transverse rows of minute 
points ; IV. each with about six oblique rows of similar teeth ; V. absent ; VI. each with 
three rows ; VII. and VIII. form a series, each with two parallel transverse rows. 
Maxillae brownish, with eight teeth below the fang. First segment longer than the next. 
Anterior feet with blunt lobes ; posteriorly the dorsal lobe is thicker and less pointed 
than in Nereis dumerilii. The bristles as a whole have shorter tips than in the latter. 
This form, wdiicli was first procured by the Eev. Mr. Eaton, of the Transit of Venus 
Expedition, seems to take the place of Nereis dumerilii. And. and Ed., of the 
European seas, and indeed it is allied in a very close manner to the latter species, and 
like it has no trace of the superior falcate bristles seen in Nereis Jcohiensis and Nereis 
toiigatahuensis. When the proboscis in a large example is opened by longitudinal section 
from the ventral surface, long and somewhat interrupted rows (IV.) of paragnathi cover 
each elevation exterior to the maxillEe, and are more or less connected in the middle line 
ventrally (III.). If opened from the dorsum, a better view (since the organs are chiefly 
ventral in position) of the median connection is obtained. It consists of five or six long- 
transverse rows. The median and two adjoining folds of the outer or buccal division 
have each two parallel transverse rows of similar small paragnathi (VII. and VIII.), the 
others are less distinct. One of the folds (the median) occasionally show^s three rows. 
Two prominent dorsal elevations of the basal ring have each two complete rows of 
minute paragnathi and a smaller one. These probably correspond to series VI. The 
paragnathi would seem to be subject to considerable variation, and probably also, from 
their small size, to injury. The general appearance of the paragnathi from the ventral 
surface is shown in PI. XXXV. fig. 6. 
It feeds on olive Fuci, masses of which occur in the alimentary canal. Branching 
Algrn and Diatoms are also occasionally met with. 
Nereis antillensis, n. sp. (PI. X X XV. figs. 7, 8, 9 ; PI. XVIa. figs. 14, 15, 16). 
Habitat. — Procured off St. Thomas, West Indies. 
Head somewhat longer than broad ; tentacles fully the length of the head. Eyes 
large and with minute lenses. Tentacular cirri very long, the second longest reaching 
the fourteenth segment. Paragnathi — L, II., and HI. absent; IV. a series of rows 
forming an angle on each side ; V. absent ; VI. each consisting of two parallel rows ; 
VII. and VIII. series of parallel rows (two in each). Maxillae pale straw-coloured at 
the base, brownish along dentary edge and tip ; eight teeth below the fang. First 
segment broader than the next. Anterior feet have a smaller and more pointed dorsal 
