the dorsal area of the upper investing membrane, and this forms the common oscular
entrance to the cavity, and stands immediately over the anal aperture. Other openings
into the infradermal cavity occur upon the abactinal surface between each of the long
lateral spines, the apertures being guarded (and can also probably be closed) by -a
modified spinelet or scale-papilla articulated on the body-frame. There are also a
number of small circular punctures distributed over the membrane, which Sars referred
to under the style of spiracula, and according to whose observations they are surrounded
with a sphincter muscle that would, in all probability, enable them to be opened and
closed at will. The superficial dermal covering contains a - number of Very fine
calcareous spicules, and the projecting tips of the supporting paxillary spinelets produce
fine asperities over its surface.
Size.—The northern specimens would appear, according to Sars’s observations, to
be larger than those occurring in the southern portion of the area of distribution.
Those taken at Finmark reach the size of 3 inches, whilst specimens from the neighbourhood
of Bergen seldom exceed 1^—2 inches; the largest size on record is 4 inches
(LutJcen).
Colow.—Sars remarks that the colour of this species is tolerably variable, the
dorsal surface being snow-white, yellowish white, or pale reddish flesh-colour, with a
round blood-red eye-spot at the tip of the arm, and the ventral surface of the animal
always white. The same author cites a small example from Finmark which was
straw-coloured, the tips of the rays orange, a few small scattered spots of the same colour
upon the dorsal surface, and the oscular aperture in the centre being also margined
with orange. Larger examples from the same coast presented the variations above
noted in comparison with specimens from Bergen.
According to the 4 Zoologia Danica,’ the animal is more of a brick-red, which
colour Liitken also states to have been retained in a large specimen sent to the Copenhagen
Museum by Capt. Holboll.
Habitat.—This Starfish occurs in 40-60 fms. depth at Bergen, and 20-100 fms.
off the coast of Finmark; in 35 fms. off Grand Manan, shelly bottom (Stimpson).
Premature Stages.—We are unfortunately not able to furnish any information
upon the characters presented by this species after it has passed the embryonic stage,
and prior to the assumption of the adult features. Sars, and also Koren and Danielssen *,
have, however, made very valuable observations upon the earlier phases, the two last-
named having traced the development of the egg, whilst Sarsf gives very admirable
descriptions and figures of the later stages of the larval form. Four of these were
found in the infradermal cavity of a specimen inch in diameter from Tromso; and
twelve young, along with two or three eggs, in one 3 inches in diameter from Vadso.
In the young individual of 1^—I f millim. in diameter, the pentagonal form is already
apparent, and three pairs of sucker-feet, together with the odd terminal tentacle, are
present in each of the radii. In thev place of the actinostome there is a large hemispherical
protuberance or knob-shaped body, equal to nearly one third of the animal’s
Fauna littoralis Horvegias, Heft 2. t Oversigt af Horges Echinodermer, pp. 5 8-62, pi. vi.
diameter, the still unresorbed remains of the larva-body; and there is yet no trace of
the future mouth-opening. Upon the dorsal surface, and surrounding the centre, are
five large tubercular prominences or wart-like knobs of the body-skin, which Sars
regarded as the rudiments of the perianal paxillse; and two similar bodies occur at the
margin of each radius, one on either side of the median line, double the size of those
just mentioned and oval in outline, which would seem to be primitive paxillse, or
rather the skin-like sheaths in which these are ultimately formed. No opening was
to be found on the centre of the dorsal surface, nor any trace of the calcareous formations
of the future Starfish.
Distribution.
a. Northward up Smith Sou/nd: Dobbin Bay, lat. 79° 40' N., 30 fins. (Nare&’s
Hoped.), the most northern locality on record.
In Davis Strait: lat. 67° 50' N., long. 55° 27' W., 20 fms. (‘ Valorous ’ Hoped).
b. North o f American Continent: Grand Manan (Stimpson); Bay of Fundy,
35 fms., shelly bottom (Verrill).
c. North of European Continent: Spitzbergen (LutJcen); Finmark (Sars); Har-
danger Fjord in Norway, the southern limit known to Sars.
Description o f the illustrations o f this Species on Plate III.
Fig. 13. Abactinal aspect of the animal: natural size.
14. Actinal aspect of the same specimen: natural size.
15. Portion near the middle of a ray, actinal aspect: magnified.
16. Portion near the middle of a ray, abactinal aspect: magnified.
Ctenodiscus corniculatus (IAncJc), Perrier. Plate III, Figs. 17-20.
1733. Astropecten corniculatus, Linck, He StelKs marinis, p. 27, tab. xxxvi. no. 63.
, 1805. Asterias crispata, Retzius, Dissert; sist.. species cognitas Asteriarum, p. 17.
1821. Asterias polaris, Sabine, Parry’s Journ. of a Yoyage for the Discovery of a H.W. Passage &c. in
1819-20, Append, p. ccxxiii, pi. i. figs. 2, 3.
1834. Asterias auranciaca, Dewhurst, Hat. Hist, of the Order Cetacea, p. 283.
1840. Astropecten polaris, Gray, Ann. & Mag. Hat. Hist. vol. vi. p. 180.
1842. Ctenodiscus polaris, Muller & Troschel, System der Asteriden, pp. 76 e t 129.
1842. Ctenodiscus pygmceus, id. ibid. p. 76.
1844. Ctenodiscus crispatus, Diiben & Koren, K. Yet.-Akad. Handl. 1844, p. 253.
1852. Ctenodiscus polaris, Forbes, Sutherland’s Joum. of a Yoyage, vol. ii., Append, p. ccxiv,
1853. Ctenodiscus crispatus, Stimpson, Syn. Mar. Invert. Grand Manan, p. 15.
1857. Ctenodiscus crispatus, Liitken, Yid. Meddel. H. Forening i Kjdbenhavn, 1857, p. 45.
1861. Ctenodiscus mnspatus, Sars, Oversigt af Horges Echinodermer, p. 26.
1862. Ctenodiscus crispatus, Dujardin & Hupc, Hist. Hat.. Zooph. Echinodermes, p. 431«
1866. Astropecten polaris, Gray, Synop. Spec. Starf. Brit. Mus. p. 3.
1866. Ctenodiscus crispatus, Yerrill, Proceed. Boston Soc. Hat. Hist. vol. x . pp. 345 and 356.
1869. Anodiscus ( = Ctenodiscus) rispatus, Perrier, Rech. sur les Pddicell. e t les Ambul. p.. 106*
H