'Alert' 1881-2

ECniNODERMATA. 165
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 10 millim. long.
Both of the specimens are white and without any dorsal median
line ; dark spots or marks prominently developed on the pinnules.
For the present, at least, I associate with A. solans a specimen
from Warrior Reef, in which the characteristic keel to the pinnule
is developed and iu which the cirri do not seem to have been moro
than twelve in number, but 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 adult ; further experience will,
I think, show them to be " dwarfs."
Prom the Arafura Sea we have received a comparatively small
specimen, which is chiefly remarkable for the smaller number of its
cirrus-joints.
In Dundas Strait there were dredged some small specimens which
approach iu 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. Solaris, but which com-
pletely eludes my attempts to understand it.
Under the name of A. alhonbtuta I was inclined to separate a specimen
from Albany Island, which is to be distinguished from the form
to which the name A. Solaris 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 that of A. Solaris, 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 and that of the two specimens
first described and unhesitatingly referred to A. Solaris, we
see that there is really a striking resemblance between the two, and
we are again led to the reflection that 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 that there
are black patches or spots on the pinnules of the first-described pair of
specitueus ; what we find in the one now under consideration is that
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, and the basal joints of the second
pinnule less strongly keeled, I propose to speak of it as A. Solaris^
var. alhonotata.
We must not be tempted by the diflSculties of specific discrimination
to make use of mere coloration :
there are in the collection two
specimens of A. Solaris from Thursday Island, one of which is uni-