-occupied by a number of small paxillse, less than those of the dorsal surface, and seldom,
«except in largely grown specimens, bearing more than five or six spinelets, and all of a
oompressed, flat, comb-like form. The paxillae are regularly arranged and closely placed
within the area, but only extend for a short distance along the ray, gradually becoming
rudimentary as the space between the “ ambulacral ” transverse combs and the marginal
series of paxillse diminishes.
The mouth-plates are large and somewhat spatuliform, having an armature arranged
«fter the following manner :~The two innermost mouth-spines are long, stout, and
directed towards the centre of the peristome ; then follow a series of about six or seven
spines placed at regular intervals apart, which radiate in the plane of the plate, one after
the other, at an increasing angle from the median line. The two most adoral mouth-
spines are much longer proportionally than the rest, which gradually diminish in size
as they approach the radial series, and being likewise curved somewhat upward from
the plane of the mouth-plate, cross and interlock with the corresponding spines of the
neighbouring mouth-angle. Between the outer margin of the mouth-plate and the side
that falls in the median line of the ray runs a more or less definite keel, upon which is
borne a secondary series of seven or eight spinelets, forming a modified comb that stands
-almost perpendicular to the plane of the mouth-plate, and runs parallel with the
marginal series or mouth-spines proper, above described.
Size.—Sars mentions an unusuallyJarge example measuring 330 millims.; but the
ordinary size seldom exceeds 200 millims., whilst the northern forms are usually much
loss; thus at Tromso 80 millims., and at Floro 100 millims. (Sars).
Colour.—Shades of red varying to purple on the upper surface and cream-colour
beneath. Occasionally in preserved specimens a trace is left of the natural red colour.
According to Verrill, this species is, in the Bay of Fundy, usually deep purple above
and orange below; one large example occurred entirely orange.
Habitat.—On stony or sandy bottoms, from low-water mark down to 90 fms.
(Liitken).
Premature Form.—In young ten-armed examples from Greenland, 10 millims. in
diameter, described by Liitken, the arms are remarkably short (2£ millims.), and the
dorsal surface is pretty closely covered with groups of 4-6 spinelets, these immature
paxilke being proportionally large and few in number when compared with those on the
mature animal. Bordering the margin of the ray there are about eight paxillse that
separate the dorsal and ventral surfaces, but do not, as in the case of older stages, lay
entirely on the ventral area. Along each side of the furrow is a series of about 14
of the transverse “ ambulacral ” combs, each of four spinelets. The ventral interbrachial
areas are still quite small, and have only very few spinelets. Each mouth-plate bears
four spines, of which the innermost is longest and is directed horizontally towards the
centre of the mouth-opening. The papulae and the spinelets composing the paxillae
increase in number with age.
We have been enabled to confirm the tenour of these observations by a small
individual dredged by Captain Feilden, during the outward voyage of the British Arctic
Expedition, in lat. 65° N., 26 miles from the coast of Greenland, at a depth of 30 fms.,
bottom rocky with rounded pebbles. This example is nine-armed, and measures 14
millims. across its greatest diameter, R = 7 millims., r= 3 millims., the length of the
arm from the tip to the arm-angle being rather less than 4 millims. The ventro-lateral
series of paxillse are about twelve in number on each side of the ray and quite marginal,
instead of being entirely on the ventral surface as in older forms. There are about
twenty of the transverse “ ambulacral ” combs between the extremity of the ray and the
mouth-plate, each composed of four spines. Each mouth-plate carries four spines on
its margin, which gives eight to the mouth-angle, and there are about two or three of
the inner secondary series present. The dorsal paxillse upon the disk are composed of
four to six spinelets, but those on the rays have seldom more than three.
Variations—This species on the whole would seem to be very fairly constant in
character, although considerable variation is manifest in the number of rays. Brandt *
notes a ten-armed variety from Sitcha; and seven-, eight-, and nine-armed forms are cited
by Liitken. The last-named observer also records a variety, taken in Iceland, Elorden,
and Greenland f , in which the rays are blunter and coarser, as well as more uniform in
thiokness throughout their length, and in which the papillae of the ventral interbrachial
spaces are more compressed and carry a greater number of spinelets (10-20). With our
present information, however, it is difficult to say what claim these modifications,
have upon our recognition.
Distribution.
a. Greenland: up to lat. 70° N., Omenak (Liitken), being the most northern locality
on record; Davis Straits, lat. 67° 50' N-, long. 55° 27' W., 20 fms., bottom of broken
barnacles and shells (‘ Valorous1 Epped.); lat, 65° N., 30 fms., rocky bottom (Nares’s
Eocped.^.
b. North o f American Continent: Newfoundland (Liitken); St. George’s Bank,
25 fms. (Verrill); Grand Manan (Stimpson); Fundy Bay and Maine, low-water mark
down to 20 fms. (Verrill).
c. North o f European Continent: Finmark, Tromso (Liitken); Iceland (Liitken);
Fseroe Islands; British Isles to S. of Ireland and the Channel.
d. Sitcha (JBrandt).
Description o f the Illustrations o f this Species on Plate III.
Fig. 5. Abactinal aspect of the animal: natural size.
6. Actinal aspect of the same specimen: natural size.
7. Portion near the middle of a ray, actinal aspect: magnified.
8. Portion near the middle of a ray, abactinal aspect: magnified.
L ophaster fu r c if e r (Duben & Koren) , Verrill. Plate III, Figs. 9-12.
1844. Chastaster borealis, Duben, (Efv. Kongl. Yet.-Akad, Eorkandl. 1844, p. 113.
1844. Solaster furcifer, Diiben & Keren, Kongl. Yet.-Akad. Handl. 1844, p. 243, pi. vi. figs. 7-10.
1862. Solaster furcifer, Dujardin & Hupe, Hist. Hat. Zoopk. Eckinodermes, p. 355.
1878. Lophaster furcifer, Yerrill, Araer. Journ. Sci. & Arts, ser. 3, vol. xvi. p. 214.
f Yidensk. Meddelelser for 1857, p. 38.
Gt 2
Prodr. Descrip, animalium &o. p. 71.