51 
The following is Dr. Johnston’s description, as given in the 
British Museum Catalogue of the British Non Parasitical Worms, 
page 205 : — 
Leucodore ciliatus. 
“Worm from 6 to 8 lines long, linear-elongate or slightly tapered 
to the tail, somewhat quadrangular, of a yellowish or flesh colour, 
with a dark red line down the middle. Head small, depressed, 
in the form of a short cylindrical proboscis, encircled with a 
raised hood or membrane. Mouth edentulous, eyes four, minute, 
placed in a square at the base of the antenna 4 , which are more 
than a fifth of the length of the body, tapered, wrinkled, and 
clothed along their inferior sides with short cilia. Segments 
numerous, narrow, distinct, the first four with an inferior papil 
lary cirrus on each side, and a brush of retractile bristles ; the 
fifth with a series of bristles curved like an italic j\ obtuse, not 
capable apparently of being protruded like the others, and having 
rather a more ventral position ; the following segments have on 
each side an obtuse branchial cirrus, originating from the dorsal 
margin, as long as half of the diameter of the body, held either 
erect or reflected across the back to meet its fellow on the mesial 
line; beneath it a small mammillary foot, armed with five or six 
sharp slightly curved bristles (crotchets?) with a small conical 
cirrus with a still more ventral position. The branchial cirrus is 
clothed on its lower aspect with rather long moveable cilia ; it 
becomes very small or entirely disappears on the posterior seg- 
ments, in which the bristles, on the contrary, appear to be longer 
and more developed. Bristles simple, unjointed. Anal segment 
conformed into a circular cup or sucker, in the centre of which 
the anus opens by a small round aperture. In this worm the 
cilia, which cover the under side of the branchial processes, are 
remarkable for their size and length, for they can be seen with a 
common magnifier fanning the water with equal and rapid beats, 
and driving the current along their surface. Their analogy with 
the cilia of Zoophytes is obvious ; but here their motion is cer- 
tainly dependant on the will of the animal, for I have repeatedly 
seen it begin and stop, and be again renewed after an interval of 
repose, and again be checked in a manner that could leave no 
doubt but that the play of the organs was entirely voluntary. 
The cilia of the antennae, notwithstanding the larger size of the 
organs, are less than half the length of those of the branchiae. 
Leucodore ciliatus lives between the seams of slaty rocks, near 
low-water mark, burrowing in the line soft mud which lines the 
fissures. Its motions are slow. When placed in a saucer it keeps 
itself rolled up in an imperfectly circular manner, lying on its 
side, and the painful efforts made to change its position, with 
little or no success, show too plainly that it is not organised to 
creep about like the Annelides errantes , but, on the contrary, that 
