from the structure ol the anterior border, the arrangement of the ventral shields,
their lateral pieces and the coloration. The Terebella gigantea of De Qnatrefages,
however, belongs to another species, whilst his T. prvdens and T. pectoralis agree
with T. conchilega.
Cunningham1 describes four long, double nephridial tubes as occurring in. segments
6_9 ; their internal openings are behind the fascicles of bristles in 5—8.
Membranous nephridial sacs are also present in segments 10—13, and they are inseparable
from one another. He found both series in communication, forming a wide, continuous
longitudinal tube from segments 6—13. Openings to the exterior were found in segments
6_9. The author draws attention to the fusion of the nephridia as approaching the
condition in the vertebrates.
A careful account of this form is given by De St. Joseph (1894). He states that the
intestine is fixed dorsally by a single mesentery, but two occur inferiorly, the blood
contains minute corpuscles (hématies), and that the heart holds a cardiac body. The
ventral nerve-cord has a neural canal containing a brownish fluid in the thoracic
region. In the anterior thoracic chamber are three pairs of segmental organs, first to
third segment, and two in the fourth, the canal opening on the fourth segment. Through
these the generative elements do not pass, for they do not enter the anterior chamber.
There are, however, four pairs of largei* greenish segmental organs in the posterior
thoracic chamber in segments 6, 7, 8 and 9. Their ciliated funnels communicate with
the coelom, and join the nephridial canals, which open on the papillæ below the bristle-
bundles in these segments. This author2 found a Polynoid (Hctrmothoe picta, De St; Jos.)
commensalistic in the tube of L. conchilega.
Dr. Elrington3 (1908) describes the larva of this form (formerly termed Wartelia by
G-iard and Nordenskiôld), and he corrects various misinterpretations, such as that the
dorsal organ, which the two authors just mentioned supposed to be ova, is in reality a
glandular structure for secreting the temporary transparent tube of the annelid. The
bilobed buccal organ he found to be muscular, not glandular. It is interesting that so
long ago as 1851 Busch4 figured this stage.
Arnold .Watson5 (1916) furnishes an interesting account of a small L. conchilega,
which ingeniously added a large fragment of gravel on its tube by supporting it with its
tentacles whilst it was fixed by sand and cement manipulated by the lips, and this though
the gap was too large to admit the fragment.
Genus CXLVII.—Loimia, Malmgren, 1865.
Cephalic lobe with inconspicuous dorsal collar; large post-oral lamella. Body
typical. Branchiae three pairs, the first the largest, arborescent, with numerous short
ultimate divisions. Seventeen pairs of setigerous processes ; bristles with winged tapering
1 ‘ Quart. Journ. Micr. Sci./ vol. xxviii, p. 248, pi. xviii, figs. 10—14.
a f Ann. Sc. nat./ 7e sér., t. v, p. 172, pi. viii, figs. 44—47, and ibid., 8e sér., t. v, p. 233.
8 ‘ La Cellule/ t. xxv, p. 103, 1 plate.
* e Beobach. u. Anat. u. Entwickl. einiger Wirbell. Th./ Taf. xi, fig. 7.
B ‘ Journ. Roy. Micros. Soc./ June, 1916, p. 253, with two text-figures.
tips. Rows of hooks commence on the second segment and extend throughout the body.
Hooks pectinate with a long anterior border with five or six teeth ; opposed back to back
in the double rows (Fauvel). Statocysts in the second segment (Fauvel). Nephridia as
in Lanice.
1. Loimia montagui, nom.nov. Plate CXIX, fig. 5—body; Plate CXXVI, figs. 1 and 1 a
—bristle and hook, and 1 b—hook of L. medusae, Sav.
Specific Characters.—Cephalic lobe has a small dorsal collar which does not join the
fan-like supra-oral arch. A large lamella, with a slight median excavation, forms a great
post-oral platform, which is differentiated into a median, more flexible region and two
stiffer lateral regions. Immediately behind is the first pair of gills; a broad fan-shaped
flap occurs midway between the second pair and the ventral scute. The fourth segment
bears the third pair and the first bristle-bundle. Ventral scutes not separated by deep
furrows, and end in a narrow ridge about the eleventh bristle-bundle. Segments marked
by narrow rings. General colour yellowish, ventral scutes rufous, shaded with purplish
black (Montagu). Seventeen pairs of setigerous processes, commencing on the fourth segment;
bristles commencing on the fifth segment, pale, smooth, golden, with tapering
winged tips. Hooks pectiniform, with a long anterior border and five to six teeth,
and no process exists on the edge of the base beneath the great fang as in L. medusae
from the Mediterranean. Posterior region has from 80 to 130 segments.
Synonyms.
1818 ?. Terebella constrictor, Montagu. Linn. Trans., vol. xii, p. 344, Tab. xiii, fig. 2.
1915. Loimia gigantea, McIntosh. Ann. Nat. Hist., ser. 8, vol. xv, p. 17.
,, ,, med/usae, Allen. Journ. M. B. A., vol. x, p. 636.
Habitat.—Devon coast, as Terebella constrictor (Montagu); Plymouth (Baird);
Plymouth (Spence Bate and B. Rowe); Yealm shore, Plymouth (Allen).
The cephalic lobe presents a small and inconspicuous dorsal collar which at each
side bends down to disappear in the general plate, and without joining the supra-oral
arch, which is fan-shaped and projects little. The space between the latter and the
cephalic collar is occupied by the grooved tentacles. From the outer border of the
cephalic region a large lamella arises, and passes with a slight median excavation to the
other side, forming thus a great post-oral platform. A differentiation on each side occurs
in the form of a curved line which extends from the segment-junction posteriorly
obliquely forward and outward, thus marking off a central and more flexible region and
two stiffer lateral regions. The great development of this post-oral flap is characteristic
of the species.
The body has the typical Terebellid outline, enlarged in front, and tapering gradually
to the posterior anus. It is rounded dorsally, flattened ventrally in front, and slightly so
posteriorly.
The segment succeeding that bearing the post-oral lamella bears the first pair of
branchiae, but is not distinguishable in the sole example available from the next segment