We are still much in ignorance as to the changes undergone by L.furcifer during
growth, whilst the records of its occurrence and structure are so few, that we prefer for
the present to regard the specimens from Discovery Bay as largely developed examples
of the species under notice, rather than to place them as independent forms, from such
scanty material.
Distribution.
a. Northward up Smith Sound : Discovery Bay, lat. 81° 43/ N. (Naves's Exped.),
the most northern locality on record ; Cape Frazer, 80 fms.
b. North o f American Continent : George’s Bank, Gulf of Maine, 150 fms. (Verrill).
c. North o f European Continent: Bergen, 30-50 fms. (Sars, Düben and Koren).
Description o f the Illustrations o f this Species on Plate III.
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.
Pteraster militaris (O. F. Müller), M. & T. Plate in, Figs. 13-16.
1776. Asterias:militaris, O. F. Müller, Zool. Dan. Prodr. p. 234. no. 2828.
1788. Asterias militaris, Gmelin, Sysfc. Hat. Linn. ed. xiii. p. 3160.
1806. Asterias militaris, Rathke, Zool. Dan. vol. iv. p. 13, tab. 131.
1842. Asteriscus militaris, Müller & Troschel, System der Asteriden, p. 44.
1842. Pteraster militaris, Müller & Troschel, System der Asteriden, p. 128, tab. vi. fig. 1.
1844. Pteraster militaris, Düben & Koren, Kongl. Yet.-Akad. S a n d l. 1844,-p. 246, tab. vii. figs. 11-13.
1850. Pteraster militaris, Sars, Nyt Mag. f. Naturv. vol. vi. p. 161.
1853. Pteraster militaris, Stimpson, Invert. Grand Mannin, p. 15.
1856. Pteraster militaris, Sars, Koren, & Danielssen, Panna litt. Norv. Heft 2, p. 55, tab. vii. figs. 1 -8 .
1857. Pteraster militaris, Lütken, Yid. Meddel. N. Forening i Kjöbenhavn, 1857, p. 43.
1861. Pteraster milita/ris, Sars, Oversigt af Nörges Echinodermer, p. 48.
1862. Pteraster militaris, Dujardin & Hupé, Hist. Nat. Zooph. Echinodermes, p. 434.
1866. Pteraster militaris, Yerrill, Proceed. Boston Soc. Nat. Hist. vol. x. p. 355.
1871. Pteraster militaris, Yerrill, Trans. Connect. Acad. A. & S. vol. i. p. 569.
1875. Pteraster militaris, Perrier, Stellendes dn Museum, p. 381 ; Arch. d. Zool. exp. et gén. vol. v. p. 301.
This Starfish is readily distinguished by the singular fin-like margin surrounding
the rays, and by the membranous skin which is supported oyer the upper surface of
the test, as well as by the largely-developed series of webbed spines that resemble fans
placed on the adambulacral plates at right angles to the direction of the furrow.
The contour of the present species is pentagonal, the body being high and arched
and the underside fiat. Proportion of disk-radius to arm-radius 1 : 2. The ossicles
of the abactinal skeleton are subcruciform, and suggest fancifully the idea of a
St. Andrew’s cross. The major diameter of these plates lies in the direction of the
ray, and their prolongations imbricate upon corresponding parts of neighbouring
ossicles, whereby it follows that the intermediate spaces are suboval or diamond-
shaped, and an apparent diagonal arrangement of calcareous plates is produced. Each
of the cruciform ossicles bears a single paxilla situated on the margin of the angle
that lies nearest to the centre of the disk. The pedicle of the paxilla is short, usually
little more than a tubercle, and hears three or sometimes four comparatively long
tapering spinelets; these diverge at a small angle from one another, and are maintained
in this position by numerous extremely fine muscular fibres, which are attached
near the tips, and pass from spine to spine in every direction over the entire area. By
this means the foundation is laid for a membranous tissue, which is supported over
the body like a tent-cloth by the spinelets, and by which the whole dorsal surface of
the animal is covered and concealed. A hollow infradermal cavity is thus formed,
wherein the development of the ova and embryos takes place*. Each of the intermediate
spaces or meshes in the calcareous network of the skeleton has a single
puncture in its membrane near the base of the paxilla, which gives passage to a papula
of very peculiar form. This remarkable organ, instead of being cylindrical with a
simple conical tip, as is usually the case, has its extremity split up into a number of
short blind cseca or knob-like branchlets, and is attached to the base of the paxilla,
being in all probability non-retractile.
Each adambulacral plate bears a transverse series of five or six long spines, which
are connected together by a membrane, and form a webbed fan that stands at a right
angle to the ambulacral furrow. The outermost spine of each comb is double the
length and thickness of any of the others, but does not always stand in a line with the
rest of the fan-like series, being sometimes nearly midway between its own series and
the next succeeding; the other spines of the “ ambulacral” comb are nearly equal in
size, the middle ones being slightly longer. The long external spines above named
extend about half their length- beyond the edge of the ray, and are united to one
another by a connecting-tissue, which forms the fan-like fringe that surrounds the
entire Starfish; and this also is the boundary of the secondary or supradertnal covering
of the dorsal surface before described. The mouth-plates are subquadrate in form; and
the mouth-spines, which are 5 or 6 in number, are webbed together and directed at an
angle downwards, the innermost spinelet being the longest and stoutest of the series.
From the centre of each mouth-plate, and standing perpendicular to its plane, is a
very large stout spine, much thicker and larger than any of the others; this is articulated
on a small rudimentary tubercle, and has the tip, which is abruptly pointed,
transparent and glass-like.
The anal aperture is situated at the centre of the inner or true dorsal surface of
the animal; and the madreporiform body, which is circular and more or less arched and
granulate or tubercular in appearance, lies in a median interradial line near -to the
centre, and not more than its own diameter away from the periproct. A moderately
wide orifice, surrounded by a circlet of enlarged paxilke, is situated in the centre of
*• For details consult Koren and Danielssen, Fauna litt. Norv., Heft 2, p. 58 j Sars, Oversigt af Norges
Eohinodermer, p. 58.