484. MR. J. WILLIAMSON A SPECIES OF 
inhabited. I have kept them alive for a week in a tank, both in and out of their tubes. 
Those in the tubes sometimes come up to the top and project the head and tentacles; 
they retire quickly when touched. Those on the gravel move very little. Ihavenever seen 
them attempt to burrow, to make a new tube, or even to move away ; but they are sensi- 
tive, and shrink when touched ; and the three lobes of the body are constantly in wavy, 
slow motion, as if their skin acted as branchize. The feet, also, beneath the segments of 
the tail, frequently move, each of the two series in its proper direction. You have, no 
doubt, observed that the pairs of feet which are placed in the centre of each segment, 
and the lower half of the disks which answer the same purpose in respect to the three 
lobes, the stomach, and the head, are so placed as to work the Annelid backwards, while 
the outer rows of feet, which bear small cirri, and the upper halves (next the head) of 
the disks above mentioned work the body forwards. The action of these members must 
be materially assisted by the very remarkable comb-like bristles with which they are 
provided. 
So far as I have been'able to ascertain by dissection, the head has no exsertile proboscis, 
nor any jaws. It contains a cup-like mouth, opening vertically when the Annelid is at 
the mouth of its tubicular home, and having a lip round nearly the entire circumference, 
and leading into a wide throat, the inner surface of which is roughly ridged. But I find 
no tongue, jaws, or teeth in it. On the upper side of the head the lip is cut, and at each 
end of the opening springs a very lithe and active tentacle, thick, obtuse at the end, 
rounded on the upper side, furrowed beneath. The edges of this furrow can meet 50 as 
almost to form a tube. Just at the root of each tentacle is a dark spot, which looks like 
an eye. I fail, however, to convince myself that it possesses any powers of vision, or to 
trace any nervous system in connexion with it. 
On each side of the head the golden feet, or lateral processes, are nine in number, 
formed of bristles, clothed with flesh. On the fourth of each series there is a group of 
bristles quite different in form and colour from the others, I should much like to know 
their probable use, as well as that of the open bag which is placed upon the back of the 
Annelid. 
Bristles I find of four distinct kinds, and I have given a drawing of each. In the two 
long processes like asses' ears, and in all the segments of the tail, the bristles are golden, 
long, straight, plain, and tapering to a plain point. In all the processes on each side of 
the head they are somewhat shorter, golden, straight or very slightly curved, truncate at 
the inner end, and tipped at the other with an elegant * spear-head,” slightly bent to the 
form of the process: these <“ spearheads ” overlap each other, and must give additional 
strength. On the lower part of the fourth lateral head-process appears a set of different 
bristles, short, thick, dark-coloured, truncate at both ends, almost club-shaped. The 
` most remarkable of the bristles are those which, placed side by side in immense numbers 
form the slight brown line observable along the edges of the feet and disks beneath the 
body. They are <“ comb-like," having eight sharp teeth, and are firmly imbedded m 
the flesh by a long tendon. The teeth of the “combs” are turned in the direction m 
which the feet respectively bearing them are required to act. The number of these little 
saw-teeth bristles in each Chetopterus must be enormous ; for many have forty segments 
