REPORT ON THE ANNELIDA. 
437 
and fourth segments ; the middle one, so far as the condition of the specimen is 
reliable, being posterior (on the fourth segment). The tijDS of the organs are not much 
tapered. 
The body presents the ordinary thickened ridges ventrally in the bristled or anterior 
region, the first being largely developed. There are fifteen pairs of bristle-bundles, the 
first with the four or five following occurring under the posterior branchia, which is 
small. The bristles have the usual wing, with, however, a long tapering extremity 
beyond it. 
Each hook (PI. XXVIIa. fig. 9) is comparatively large, and has five teeth, which 
approach each other in size, the first and last, however, being less than the three median. 
The inferior fang, which in the majority of the allied forms is largest, is of moderate size 
and less acute than the others. Below it is an acuminate spike with a broad base ; and 
the anterior inferior process is somewhat pointed. The dorsal line is short and deeply 
incurved in the middle. The basal margin, again, has a convexity so slight that it 
appears almost straight till it approaches the curvature at the anterior inferior 
process. 
About thirty-one segments occur behind the last bristle-bundle, besides the anal or 
terminal, though the specimen is somewhat injured in this region. Each somite bears 
only the processes for the hooks. The lateral muscular bands alluded to in the former 
species are very distinct. 
The intestine contains a little greyish mud, which shows a few Diatoms and fine 
siliceous needles. 
The tube is composed of minute sand-grains, small arenaceous Foraminifera, fragments 
of Radiolarians and sponge-spicules, with other minute organisms, the whole having the 
colour of sand with a few pale spikes. The opalescent lining-membrane is easily 
torn. 
The body-wall is too soft for complete examination, but in section the hypoderm 
presents the average development, and the flattened nerve-cords occur below the some- 
what wide area between the longitudinal ventral muscles. A slight interval separates 
the longitudinal dorsal muscles. The other points conform to the typical structure. 
The perivisceral cavity contains abundant male elements. 
An empty tube was trawled at Station 244, June 28, 1875 ; lat. 35° 22' N., 
long. 169° 53' E. ; depth, 2900 fathoms; bottom temperature 35°’3, surface tempera- 
ture 70° '5 ; sea-bottom, red clay. It probably belongs to an allied form, and is decidedly 
tougher than the foregoing. The greyish-brown mud on the tube contains Diatoms, 
minute Foraminifera, the same triradiate Radiolarian formerly seen, as well as others, 
fragments of sponge-spicules, and minute sand-graius. 
