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washed with purple; the middle line of the arms is lighter, but
patches or spots of purple are to be found at the sides ; the lower
surface is a little lighter on the disk than on the arms, where it is
almost black.
Port Molle, 12 fms.
Three smaller specimens already in the collection of the British
Museum, from Nicol Bay, N.W. Australia, must, I think, he
referred to this species. The smallest of these has not more than
30 cirri, nor have they more than 40 jo in ts ; their spines, and especially
the penultimate one, are better developed. There are only
about 50 arms, and in some cases there are only two palmars (when
the axillary is not a syzygy). The ground-colour is purplish, marked
with yellow bands.
16. Actinometra Solaris.
P. H. Carpenter, Notes Leyd. Mus. iii. p. 192; Journ. Linn. Soc., Zool.
xvi. p. 614.
Two specimens of different sizes do, I think, undoubtedly belong to
this species, to which specimens have not unfrequently been assigned
th at are to he distinguished by what are apparently good specific
characters.
Prince of Wales Channel.
The greatest difficulties attend the exact delimitation of the specific
characters of this species; and the question whether they vary within
wide limits or are, rather, sharply defined cannot yet he answered.
For the purposes of exact knowledge it seems to be at present the
better course to try and recognize points of difference between
allied forms; we must by experiment and experience discover which
of the characters of a Comatulid afford trustworthy criteria in the
discrimination of species ; so few forms have, as yet, been described,
and so little criticism has been brought to bear on what work has
been done, th at our knowledge of how species are to be defined and
delimited is as yet in a very elementary condition.
The only consolation is to be found 'in the reflection th at what
may seem, with wider knowledge, to he a “ had species ” is justifiably
regarded now as a “ good one,” and th at wary specific discrimination
is often a considerable aid to the exact and accurate knowledge
of the characters of complex and elaborate forms.
The two specimens here ascribed to A . S o la r is present the following
characters :—■
There are 12 cirri, and there may he only 18 joints in a
c irru s; the more proximal joints of the arms of the smaller specimen
are more “ knobby ” than the correspondingly placed joints
in the larger. In both cases the arms are at their widest a httle
distance from the disk; the keels on the basal joints of the second
pinnule aro well marked in the smaller specimen ; hut in neither
case are there any very prominent keels on the basal joints of the
third pinnules.
Arm of the larger specimen about 120, of the smaller about
85 millim. long ; in the former the first pinnule is about 20 and the
cirri 16 millim. long.
Both of the specimens are white and without any dorsal median
lin e ; dark spots or marks prominently developed on the pinnules.
For the present, a t least, I associate with A . S o la r is a specimen
from Warrior Eeef, in which the characteristic keel to the pinnule
is developed and in which the cirri do not seem to have been more
than twelve in number, hut in which the number of cirrus-joints
would appear to be less than fifteen.
There are also specimens from Port Curtis and Torres Straits
which, though still small, hardly promise to ever have the stout arms
which are so characteristic of the a d u lt; further experience wiU,
I think, show them to he “ dwarfs.”
From the Arafura Sea we have received a comparatively small
specimen, which is chiefly remarkable for the smaller number of its
cirrus-joints.
I n Dundas Strait there were dredged some small specimens which
approach in character A . pectinata and A . purpurea, but give us,
with our present scanty information, but little aid in determining
the character or limits of these species.
From Thursday Island we obtained a somewhat injured and large
specimen belonging to the “ type ” of A . S o la r is , but which completely
eludes my attempts to understand it.
Under the name of A . a lh o n o ta ta I was inclined to separate a specimen
from Albany Island, which is to he distinguished from the form
to which the name A . S o la r is is ordinarily restricted by the larger
number (20-25) of cirri, and the less prominent keels on the basal
joints of the second pinnules. The general facies, however, of the
specimen is distinctly th at of A . S o la r is , with the exception of the
rather remarkable coloration, which has led to the proposal of a
distinctive name. When, however, we make a careful comparison
between the pattern of this coloration aud th a t of the two specimens
first described and unhesitatingly referred to A . S o la r is , we
see th at there is reaUy a striking resemblance between the two, and
we are again led to the reflection th at great circumspection is to be
exercised whensoever we are tempted to make use of difference in
colour as a distinguishing mark. I have already stated th at there
are black patchas or spots on the pinnules of the first-described pair of
specimens ; what we find iu the one now under consideration is th at
these spots having greatly increased in number, and become more extensive
than the white, have caused the white ground to assume the
appearance of spots on a dark ground. The extreme limit of the
species seems, however, to be reached by this form; and as the cirri
are more numerous than usual, aud the basal joints of the second
pinnule less strongly keeled, I propose to speak of it as A . S o la r is ,
var. a lh o n o ta ta .
We must not be tempted by the difficulties of specific discrimination
to make use of mere coloration ; there are in the collection two
specimens of A. S o la r is from Thursday Island, one of which is uru-
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