clavate papilla. These papillae were well marked in a series of comparatively small
pale examples brought by Canon Norman from Finmark. The larger coloured specimens
showed them less distinctly. The spines are larger in certain arctic examples,
e. g. from Davis Strait. The cilia differ much in length even in large specimens. Some
of the scales in spirit-preparations adhere with great tenacity; others separate readily.
Their colour varies much, being, to take the order of Malmgren, bluish grey,
greyish, brownish, or dark brown with a purplish or violet lustre, reddish brown
(Vandyke brown), almost black, or greatly variegated. A striking variety has pale buff
scales bordered with a narrow belt of dark brown. Others agree with the foregoing
except that the scale is darker brown (Bismarck), with a small white patch in the centre
and a few darker grains in front, the whole forming a beautiful series. Some have the
outer half of the scales whitish, the inner blackish grey or brown, so that the animal
has a broad blackish or brownish band down the centre. Occasionally the pale fawn-
coloured scales are minutely and uniformly speckled with small brown touches. A few
again are almost white. Some have a broad brownish-red belt, almost a third the
breadth of the scale, curving within the posterior border, and as these are arranged
symmetrically the effect is agreeable. A developing scale shows minute clavate cilia
before the spines appear.
Development of the Scales.—These seem to be reproduced with considerable rapidity,
forming miniature scales on the end of the peduncles, with a trace of brownish pigment
over the scar. They consist of a superficial cuticle, which is quite smooth, and of a
subjacent cellular layer within which the connective tissue rapidly proliferates.
Feet.—The first foot has often only a single bristle, conforming to the dorsal
type.
The second foot has a short ventral lobe and a long ventral cirrus with clavate
papillae. The dorsal bristles are smaller, shorter, and more curved than usual, but
are otherwise of the normal structure. The ventral are much more slender than the
normal, and the spinous region is proportionally long and hispid, while the smooth tip
is slender and simple.
The third foot has much stronger dorsal bristles than the second, and the ventral
bristles have also increased in size. In these the upper and lower groups still have
simple tips, while the median series have bifid tips, but the region is more slender than
in the typical foot, and the secondary process small. The spinous rows are also more
hispid (i. e. have longer spines) than in the typical foot.
As we proceed backward the characters of the typical foot are acquired (Plate XXX,
fig. 1). I t shows dorsally a strong series of somewhat straight or only slightly curved
bristles with well-marked spinous rows, and a smooth spear-shaped tip of some length
(Plate XXXVIII, fig. 14). In examples from Greenland the tips of these (dorsal)
bristles are so elongated as to be almost sabre-shaped. In specimens from Cornwall,
again, the spinous rows are finer, and the bare portion at the tip somewhat differs. In
young examples the front edge is slightly bevelled. The ventral division bears a series
of strong bristles, every one of which has a bifid tip. In the upper series the smooth
portion at the tip is slightly curved outward, a,nd the secondary process is short and
sharp (Plate XXXVIII, fig. 15). The terminal hook is well marked. In those with
short tips from the middle of the foot (Plate XXXVIII, fig. 16) the same relations of the
secondary process occur, and thus they are easily discriminated from the bristles of
Lagisca Jloccosa. The ventral cirrus has a series of short clavate cilia.
In the terminal feet the dorsal bristles remain stout, but their tips are more
tapered. The slender ventral bristles, on the other hand, have.the spinous region
greatly elongated, but the delicate tips in most cases retain the bifid condition, only one
or two at the ventral border being simple.
Varieties .—A variety procured by Canon Norman in Norway has shorter bristles,
but though the rows of spikes on the dorsal bristles are somewhat finer, in all other
respects it corresponds. In another from Loch Portan, Lochmaddy, the dorsal bristles
immediately above the ventral are slender, and in this form also the scales have more
numerous and longer cilia. The colours are brighter, and the under surface and sides
pinkish.
A pale variety, having somewhat rougher scales with longer cilia, occurred between
tide-marks at Lochmaddy.
The large arctic examples, such as those of Dr. Walker, have a distinct tendency
to elongation of the tips of the bristles, both dorsally and ventrally; while a variety
from St. Andrews presents more elongated dorsal bristles than in the typical example.
Few annelids are more abundantly distributed, yet the structural variation of the
individuals is not great.
Habits.—H. imbricata lurks under stones in pools and moist places between tide-
marks, among sponges and in their crevices, in tubes of Terebella and Chsetopterus}
in empty acorn-shells, and in almost any convenient crevice. It is one of the most
plentiful forms between tide-marks, and is also dredged abundantly in the laminarian
region and beyond it, in the crevices of old shells, tangle-roots, and stones. I t clings
closely to such surfaces, and apparently tries to escape observation. Young examples
have been found in old shells with Polycirrus. It is most active and restless when
disturbed, and wriggles violently, leaving fragments of the body or separated scales in
the hands of the captor.
It is a somewhat delicate animal in confinement. Thus it suffers rapidly in a
bottle with other marine animals on the collecting ground; indeed, if the search be
prolonged few are alive, while other marine forms survive. Sir J. Dalyell, however,
retained them until the discarded scales were reproduced, being scarcely distinguishable
from the original scales in about six weeks or two months. I t swims with an undu-
latory motion in the water, but, like the loach, soon sinks to the bottom. As in allied
species, it often strikes the glass vessels with its jaws, making sounds heard at a
considerable distance.
It is brilliantly phosphorescent, discharging bright bluish-green or greenish scintillations
from the point of attachment of each scale, and thus under irritation the flashes
are arranged in pairs along the body or in a double moniliform line. The separated
scales also continue to gleam for some time, chiefly at the scar for attachment, that is
near the great ganglion of the region. If severely pinched it wriggles through the water,
emitting sparks of greenish or bluish-green light from the foregoing points. The phos-
42