'Alert' 1881-2

ECHINODERMATA, 125
7. LincMa marmorata.
Ophidiaster marmoratus, Michelin,Mag. Zuol. 1845, Zooph. p. 21, pi. 10.
Liuckia marmorata, Perrier, p. 13o.
If I am correct in referring to this species a series of specimens
from Port Molle and Fitzroy Island, it will be easy to understand
how it is that M. Michelin's species was never again recognized till
the Paris Museum came into the possession of his type ;
that would
appear to be the only example that they possess, and, as M. Perrier
points out, the " typo " is obviously young. The specimens before
me are clearly enough all representatives of the same species ; but
were any one of them described it is quite possible that from the
description alone of that single specimen it would be easy to regard
some others of the series as belonging to another form.
In the first place, though all the specimens are provided with the
intermediate plate that connects into a pentagon the terminal one of
the " ranges de plaques qui occupe la ligne mediane dorsale de
chaque bras," the extent to which this is evident varies a good deal,
and one would hardly think it worthy of especial note in the largest
example were not attention directed to it by the better-marked
characters of some of the smaller. Secondly, the smallest specimen
has the dorsal plates covered with coarse granulations ; of some of
these, at any rate, it would be appropriate to say (again quoting
Perrier) " les granules voisins de leur centre sent un peu plus gros
que les autres;" on the other hand, one, two, or more granules
near the centre acquire, in the larger specimens, a much greater
predominance, and give a somewhat different appearance to the
creature ; in the largest specimen these again have disappeared, and
the whole surface of the plates is more uniformly granular. Thirdly,
the dorsal plates may lose the regularity of outline which is so well
marked (if not exaggerated ?) in Michelin's figure, and which is
expressed by M. Perrier in the words " sensiblement carree," and
become narrower at the angles at which the pores are placed ; this
is perhaps due to the greater development in the number of pores,
of which as many as seven may in some cases be found within the
limits of one area. Lastly, it is only in the smallest specimens that
we find a double row of tubercles fringing the adambulacral spines ;
in aU the larger specimens the row is single, or, in other words, one
row of tubercles ceases to grow proportionately, and becomes obscured
in the general granulation of the actinal surface.
The only considerable point of difference between these specimens
and that figured by Michelin lies in the remarkable coloration of
his specimen ; if, however, M. Desjardin's example from the island
of Mauritius was immediately dried, it might have retained its colour :
while Dr. Coppinger's specimens, which were placed in spirit, might
very possibly have had part of their colouring-matter dissolved out.
The largest example has E equal to 50 miUim.
Prince of Wales Channel, 7 fms.