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THE VOYAGE OF H.M.S. CHALLENGEE. 
while posteriorly these organs are bifid. The branchia springs, along with the dorsal 
cirrus, from a common trunk, the main stem after a short interval giving off a very 
long branch, and after a somewhat longer interval, another about the same length, and 
then terminating in a third elongated process. 
The filiform dorsal cirrus is about a third the length of the branchial process next 
it. The superior bristles have a long straight shaft, and the slightly winged tapering 
tip is bent at a distinct angle. The brush-shaped bristles are very numerous, and 
their extremities are peculiarly flattened (slightly spoon-shaped), and have nine or ten 
filaments. 
The compound bristles (PI. XXa. fig. 23) have also somewhat long shafts, with 
slightly curved and flattened ends. The terminal piece is rather elongated, and the 
edge of the guard, which runs to the base of the process, is nearly straight. The 
inferior fang is large, the terminal comparatively small. 
The foot (PI. XXXIX. fig. 11) has' a single dark brown spine. Inferiorly are one 
or two hooks (PI. XXa. fig. 24) which have an evident constriction a little below the 
tip. The terminal hook or process is curved, and the chief fang below comes off nearly 
at a right angle from the extremity. 
The intestine of this form contained tough masses, which readily turned the edge 
of a knife, crowded with large, beautifully reticulated, translucent, and apparently 
homogeneous chitinous tissue. These may have been parts of the skeleton of a sponge 
or similar structure, especially as they were enveloped in softer granular substance. 
The space between the large ventral longitudinal muscles in section is wide, 
probably from its posterior position. The hypoderm is of considerable thickness, and 
forms a curved projection externally. The neural canal lies a little above the circular 
muscular coat. A strong band on each side of the nerve-area, chiefly from the vertical 
muscle, passes downward. The somewhat thin dorsal longitudinal muscles are pierced 
by the vertical, an arrangement which probably causes the flattening of the body as in 
the leech and similar forms. A minutely granular substance, apparently male elements, 
exists at the bases of the feet. The alimentary canal in this region lies close above the 
nerve-area, the pedicle being short. 
Eunice harvicensis, n. sp. (PI. XXXIX. fig. 12; PI. XXIa. figs. 1—3). 
Habitat . — Found between tide-marks at Bermuda in June 1873. 
One specimen, which is partly dried and incomplete posteriorly, measures about 
48 mm., and at its thickest part in front 4d mm. in diameter. Two fragments of the 
posterior region also occurred. 
From the condition of the specimen very little can be said about the head. The 
