502 
THE VOYAGE OF H.M.S, CHALLENGER. 
The dorsal surface of the body is smoothly rounded, from the tip of the tail forward 
to the cephalic groove. The thoracic region is marked by a pale band, which is the 
continuation of the ventral groove. The ventral surface is flattened, and a furrow, 
commencing posteriorly at the tip, splits the scutes in the middle line ; but when it 
reaches the fourth behind the thoracic region it deviates a little to the right and 
finally passes obliquely through the last one to the groove between the posterior 
thoracic foot and the first abdominal, and becomes continuous with the dorsal 
band formerly mentioned. A distinct pajDilla occurs on each side of the ventral 
groove in the anterior scutes of the abdominal region, and these processes also exist 
in the same position (though the groove has disappeared) on the three adjacent 
thoracic scutes. 
The cephalic region has dorsally a deep furrow, surmounted along each edge by a 
continuation of the cephalic collar, which forms an accessory flap on each side. It is 
rendered the more conspicuous by a deep brownish belt a little below the edge. The 
collar, which is folded outward in the example, continues without break to the ventral 
median fissure, and terminates in a triangular reflexed flap on each side. The inner 
edge of the flap has a dark brown band of pigment. The general colour of the body is 
pale madder-brown, deeper in front, while the branchiae have a deep chocolate-brown 
base. In the posterior region a dark spot occurs at the base of each setigerous process, 
and another at the end of the uncinigerous row. 
The anus is directed dorsally rather than ventrally. 
The anterior or thoracic region consists of the typical eight segments. The 
bristles of the upper series somewhat resemble those of Dasyclione japonica, 
the wings, however, being slightly more pronounced (PI. XXXIa. fig. 1). The 
inferior series present the same differences from the foregoing in regard to the tips, 
which are proportionately shorter (PI. XXXIa. fig. 2). The usual elongation occurs 
in the tips of the posterior bristles. Both series are thus allied to those of Dasychone 
japonica. 
The anterior hooks (PL XXXIa. fig. 3) possess an elongated neck, with a compara- 
tively small inferior prow. The finely serrated edge above the great fang is of 
moderate length, and the crown of the hook is somewhat truncate with a central 
dejDression. The posterior or dorsal line is nearly straight, or only slightly convex. 
The posterior basal appendage is fairly developed, and elevated above the ventral line 
which curves upward to join it. 
Few Diatoms occur in the contents of the intestine, but minute Radiolarians, with 
sponge-spicules, minute ova, bristles of one of the Lumbrinereidse, a parasitic Crustacean 
of a few segments, and fragments of Pteropod shells are present. 
