the Starfish; and, further, in some examples the disk-spinelets are also rather longer
than those which are found upon the rays.
■ The papulae are single. The pedicellarise are not crowded, and generally either
isolated or only two or three together. Pedicellarim forcipiformes are as a rule not
very numerous upon the dorsal surface of the rays, except towards the extremities where
they occur somewhat more abundantly. Those which accompany the lateral spines are
situate near the middle of the shaft. Pedicellarim forficiformes form a fringe along
the sides of the ambulacral furrow. The madreporiform body is situated near the
margin, and is frequently almost concealed by the spinelets that surround it.
&sse.—This comparatively small species measures from 35 to 50 millims in diameter
none of larger size having been recorded.
Colour. According to Inspector Olrik's observations, made during life, small
examples of A. grcmlandicum are described as of a greyish colour on a violet ground, and
arger ones of a grey olive-green. All the specimens preserved in spirit which we have
examined are entirely bleached, whilst the dried ones are of a dirty yellowish grey.
Hahitat. Mr. Barrett has taken this Starfish upon rocks near the shore; Insp. Olrik '
reports that he has dredged it at very various depths; and Capt. Feilden obtained the ■ B Hi 0f 80 fathoms- off CaPe Frazer, during the British Arctic Expedi-
tion of 1875 76, under Capt. Sir George Nares.
Variations. In this species considerable variation occurs in the general form and
habit of the Starfish, as weU as in the spinulation borne by the calcareous network of
the test. There may, in fact, be set apart a long, thin-armed variety with the rays tapering
but slightly, and another form in which the rays are broad, short, and sharply
tapering at the extremity. The difference of charactefpresented by the spinulation is
perhaps even more conspicuous. • In some specimens, for example, the spinelets of the
abactinal surface of the rays are confined mainly to the groups that stand at the intersections
of the network, the intermediate portions of the ossicles bearing only isolated spine-
lete, few and tar between; whilst in others a very marked divergence is produced by
the occurrence of well-developed and comparatively clustered groups of spinelets upon
the intercalary pieces, as well as an increase in the number of those composing the main
senes. The effect of this tendency to develop an increased number of spines is perhaps
most staking in its result on the lateral series, where, in consequence of the intercalating
ossicle bearing a supplementary spinelet, an additional and intermediate longitudinal
senes is formed between the dorsal and ventral rows of lateral spines, extending in some
cases ^almost to the extremity of the ray; and besides this, it not unfrequently happens
that the development of extra spines is carried to such an extent that a regular redu-
plication of several of the lateral spinelets at the base of the rays takes place
I t must be remarked, however, that, beyond the simple record of the facts, the
amount of material at our disposal is insufficient to wanant the expression of any decided
opinion as to the significance which these modifications may bear; for, although at first
sight it would seem probable that these were only the conditions of age and growth a
careful study of the specimens which we have examined, together with the consideration
of the influence of habitat, lead us to favour the belief that the structural changes above
noted may mark the effect of conditions of environment, and thus represent the steps of
an actual locational divergence in the species under notice. A much larger series is
needed, however, from various localities, before a definite statement can be made upon
this subject.
Distribution.
a. Northward o f Smith Sound: Discovery Bay, lat. 81° 41' N., 25 fms. (Nares's
Exped.), the most northern locality on record; Port Foulke (Stimpson).
b. North o f American Continent: Assistance Bay (under the name of JJraster
molaceus, Forbes, Penny’s Exped.)-, Labrador (Packard)-, Newfoundland (iMtken)-,
Gulf of St. Lawrence, near Anticosti (Verrill) ; Grand Manan (under name of A.
Mulleri, Stimpson).
c. North o f European Continent: Off S.W. coast of Novaya Zemlya, lat. 71° 6' N.,
long. 50° E., 62 fms. (‘Willem Barents' Exped.).
Description o f the Illustrations o f this Species on Plate II.
Fig. 9. Abactinal aspect of the animal: natural size.
10. Actinal aspect of the same specimen; natural size.
11. Portion near the middle of a ray, actinal aspect; magnified.
12. Portion near the middle of a ray, abactinal aspect: magnified.
Stichasteb albulus (Stimps.), Verrill. Plate II, Figs. 13-17.
1842. Asteracanthion roseus (pars), Müller and Troschel, System der Asteriden, p. 17.
1853. Asteraccmthion albulus, Stimpson, Syn. Mar. Invert. Grand Manan, p. 14.
1855. Asteracanthionproblema, Steenstrup, Yid. Meddel. N. Forening i Kjöbenhavn, 1854, p. 240.
1857. Asteracanthion problema, Lütken, Yid. Meddel. IT. Forening i Kjöbenhavn, 1857, p. 30.
1863. Asterias albula, Stimpson, Proc. Acad. N. Sci. Philad. 1863, p. 142.
1866. Stichaster albulus, Verrill, Proceed. Boston Soc. Nat. Hist. vol. x . p. 351.
1875. Stichaster albulus, Perrier, Stellérides du Muséum, p. 8 2 j Arch, de Zool. exp. et gén. vol. iv.
p. 346.
A small Starfish with narrow disk and rounded or somewhat arched rays, the number
of which is almost invariably six, three rays on one side being as a rule very much
shorter than those on the other. Proportion of the diameter of the disk to that of
the arms 1: 5 or rather more. The ambulacral furrows are wide, with suckers arranged
in zigzag series, forming two or four rows, according to age and size. Each adambu-
lacral plate bears two “ ambulacral” spines which radiate slightly right and left, and
form regular rows ; occasionally in larger specimens an additional spine accompanying
the ten or twenty innermost pairs of the ray. Closely succeeding to these, there follows
on the side of the arm a slightly oblique series of three (or, in large specimens,
four) similar spinelets, representing ventro-lateral spines, but not always a series opposite