16 
THE VOYAGE OF H.M.S. CHALLENGER. 
nineteen segments. The opalescent bristles (milk-white in life) project nearly as much 
on each side as the breadth of the body. Posteriorly it terminates in two elongated 
styles. The head bears a large and somewhat spongy, rugose caruncle, which extends 
backward at least to the fourth segment. The folds almost separate from each other on 
manipulation, and their looseness affords a distinctive feature when contrasted with those of 
Chloeia jiava and others. No eyes are visible in the specimens. In front of the caruncle 
is the median tentacle, which has about the same proportional length as in Chloeia. It is 
tinted of a dark greenish hue superiorly. After a longer interval than in Chloeia a pair 
of tentacular cirri, also slightly tinted superiorly, occur at the anterior border of the 
snout. The other pair (similarly coloured) are situated at the sides of the anterior labial 
processes. The latter are well developed, and homologous with those in Chloeia. The 
posterior border of the mouth is formed by the second body-segment instead of the^ 
fourth as in Chloeia. The segments of the body have a comparatively large antero- 
posterior diameter, the median five or six being conspicuous in this respect. A 
tyjDical segment bears on each side of the middle line a dorsal branchia, a tuft of long 
opalescent bristles, two dorsal cirri, a ventral tuft of long bristles, and a ventral cirrus. 
The branchiae seem to commence on the fifth segment, and when fuUy developed 
consist of a short trunk bearing three or four simple pinnae, and an external basal division 
of a few processes. These organs are softer than in Chloeia jiava, and their hypodermic 
tissue is less compact. A series of muscular fibres runs from base to apex along the main 
stem, and in the pinnae fibres occur within the hypoderm at each side in ordinary views. 
The dorsal bristles are opalescent and elongated, especially posteriorly, so that the 
body of the animal is enveloped in a kind of chevaux defrise by the crossing of the 
bristles anteriorly and posteriorly. Each bristle may be described as a long fusiform 
structure, the base equally with the tip tapering to a fine point. The shaft gradually 
dilates upward, then diminishes somewhat below the fork, where a little enlargement 
occurs. The elongated limb beyond the bifurcation has a slight bend opposite the tip of 
the shorter, and in the best developed a series of serrations occurs on the outer border of 
the long limb (PI. Ia. fig. 10), the points being directed downward in the ordinary way. 
Others show a slighter array of serratures along the edge next the fork (PL Ia. fig. 11), 
while a third and somewhat shorter set (PL Ia. fig. 12) appear to be quite smooth. 
These bristles have a very thin external crust, and are somewhat less brittle than in 
Chloeia Jiava. The air alluded to by Claparede probably gained entrance into the 
bristles of the latter through cracks. The anterior dorsal bristles have stouter though 
shorter tips, with all the markings boldly developed, especially the serrations on the 
side next the fork. The point of insertion is much more slender than the distal end. 
Those towards the extremity of the tail, again, are characterised by very elongated tips 
and distinctly serrated outer margins, as in PL Ia. fig. 10. 
The ventral bristles form long asbestos-like tufts, which make a remarkable fringe. 
