MYXICOLA INFUNDIBULUM. 311 
with one another in the cerebral commissure. A single neural canal, at first (some distance 
behind the cesophageal ring) on the left, then becomes central, the cords being on either 
side of it to the posterior end of the body. He observes that the cords are completely 
separated from the epidermis, whilst in the Sabellids they are not so—a conclusion which 
differs from that shown by the author in 1877,' and held now. 
Grube (1855) adopted the title Myxicola of Koch. He included it as a genus of the 
Sabellids, as indeed he did long before in his © Familien’ (1851). 
This group was included in his family Serpulidee by De Quatrefages (1865) and ranged 
along with the Sabellidee. 
Levinsen (1883) follows Malmgren in retaining this group as a separate family, and he 
adopts Claparéde’s title Leptochone, his only species being Leptochone Steenstrupr, Kroyer. 
The species of Myzxicola group themselves under two divisions, viz., those with the 
beaked crotchets in the longer anterior region, and those with the simply hooked crotchets 
in the shorter anterior region. The posterior hooks in all retain greater uniformity. 
1. MyxIcoLa INFUNDIBULUM, Montagu, 1808. Plate CXIV, fig. 4—body; Plate CXXX, 
figs. 4—4c—bristles and hooks. 
Specific Characters—Cephalic plate devoid of a collar; a triangular process passes 
forward in the mid-dorsal region between the branchial fans, and ventrally a slight pro- 
jection also occurs between them. Closed statocysts. Branchiz not caducous ; filaments 
twenty-one to thirty-seven in each fan, connected by a web almost to the tip as in Chone, 
and having a chordoid axis, a slender continuation being carried into the terminal filament, 
which has a tapering web on each side and is often tinted dark purple. Pinne long with a 
chordoid axis, not jointed, and they taper a little from base to apex. Distally the pinne 
form a short alternate double row. Branchial plumes of a rich dark chocolate brown, the 
pinne being purplish red. The bases are dull orange like the colour of the body. Body 
2—10 inches in length and having 45—150 or 160 two-ringed segments, somewhat fusiform, 
for it is narrowed in front and tapers posteriorly ; rounded throughout except anteriorly, 
where on the ventral surface a groove (sillon copragogue) passes backward to the eighth 
segment, which it cuts obliquely as it goes to the right and ends dorsally about the middle 
of the ninth. Posteriorly the body terminates in an anus at the blunt tip. It is of a dull 
orange hue, and in the Zetlandic specimens a white ring encircled the body in front of the 
third segment-junction. The anterior region has eight segments. Bristles uniform 
throughout with long, straight, cylindrical shafts and finely tapered though rather short 
tips and narrow wings slightly bent backward. Posteriorly the bristles are more minute and 
more slender and the shafts are tapered toward the tip, which has a curvature as in front and 
a trace of wings. Anterior region has groups of about eight long crotchets which somewhat 
resemble those of Oligochets. The shaft is long, curved, tapered inferiorly, dilating at its 
distal third into a shoulder from which it is gently diminished to the throat. Neck stout 
and nearly straight; main fang arises at a wide angle to the neck, is blunt, and the crown 
above it, which slopes downward in lateral view, has a few small teeth. Posterior hooks 
1 “Proc. Roy. Soc. Edin.,’ Session 1876-77, pp. 11 and 12, sep. copy. 
