468 
THE VOYAGE OF H.M.S. CHALLENGER. 
from base to apex, but are not much attenuated at the tip. A second pair, similar in 
all respects, occur at the anterior border of the third segment. They are thus fewer than 
in Eutlide'pus setuhalensis, and vary in position, for the anterior pair are nearer the 
middle line than the posterior. 
Twenty pairs of bristle-tufts apparently are present, but as the specimens are much 
softened and ruptured this determination is questionable. The bristles (PI. XXYIIIa. 
fig. 14) have a pale golden lustre, and, tliongh some are shorter than others, do not 
show the marked division into groups so characteristic of Thelepus and the Terebellidse. 
They taper from a short distance above the base to the tip, which has narrow wings, 
the extremity in many showing a slight enlargement at the termination of the wings. 
The bristles are thus somewhat intermediate in structure between the two families above 
mentioned. 
The hooks (PI. XXVIIIa. fig. 15) ajDproach those of the previous species, having one 
evident tooth above the great fang, and a smaller and less distinct one superiorly. 
The space below the fang is much larger than in Euthelepus setuhalensis, and the tip 
of the niucro is more globular. The anterior inferior angle is smoothly rounded so 
that the aspect of this region differs notably from that of the former species. The 
dorsal outline is similar, but the ventral is less convex than in Euthelepus setuhalensis. 
The posterior hooks have the anterior inferior angle less rounded, and occasionally more 
than two teeth occur above the great fang. 
The brownish mud in the alimentary canal presented a few Diatoms and fragments 
of sponge-spicules, a few small Glohigerinm and arenaceous Foraminifera (aj^parently 
with muddy tests), peculiar conical Radiolarians with an acutely pointed apex, and 
other forms. 
The animal forms a massive tube composed of dark brownish mud surrounding the 
usual chitinous lining. Scattered here and there amongst the mud are globular 
arenaceous Foraminifera of a somewhat ochreous tinge and about the size of No. 12 
shot, and occasionally a cylindrical tubular form of the same kind. In minute 
characters the mud of the tube corresponds with that in the alimentary canal, only 
Diatoms and Radiolarians are rare, and small arenaceous Foraminifera and rough sand- 
grains more abundant. 
The hypodermic layer is also much developed ventrally in this species, especially 
towards the median line, over the nerve-area. By the bending inward of the circular 
coat in the latter region the longitudinal ventral muscles almost form a semicircle and 
are less massive than in Euthelepus setuhalensis. The oblique muscles are of consider- 
able strength. The nerve-cords are similar in shape to those of the former species, but 
are proportionally less. 
