at the bottom of a deep burrow. It feeds on the fallen fruit of this
tree by tearing off the husk, fibre by fibre; and it always begins at
that end where the three eye-like depressions are situated. It then
breaks through one of these eyes by hammering with its heavy front
pincers, and turning round, extracts the albuminous core with its
narrow posterior pincers. But these actions are probably instinctive,
so that they would be performed as well by a young animal as by an old
one. The following case, however, can hardly be so considered: a
trustworthy naturalist, Mr. Gardner (14. Travels in the Interior of
Brazil, 1846, p. 111. I have given, in my Journal of Researches, p.
463, an account of the habits of the Birgus.), whilst watching a
shore-crab (Gelasimus) making its burrow, threw some shells towards the
hole. One rolled in, and three other shells remained within a few
inches of the mouth. In about five minutes the crab brought out the
shell which had fallen in, and carried it away to a distance of a foot;
it then saw the three other shells lying near, and evidently thinking
that they might likewise roll in, carried them to the spot where it had
laid the first. It would, I think, be difficult to distinguish this act
from one performed by man by the aid of reason.
Mr. Bate does not know of any well-marked case of difference of colour
in the two sexes of our British crustaceans, in which respect the sexes
of the higher animals so often differ. In some cases, however, the
males and females differ slightly in tint, but Mr. Bate thinks not more
than may be accounted for by their different habits of life, such as by
the male wandering more about, and being thus more exposed to the
light. Dr. Power tried to distinguish by colour the sexes of the
several species which inhabit the Mauritius, but failed, except with
one species of Squilla, probably S. stylifera, the male of which is
described as being of a beautiful bluish-green, with some of the
appendages cherry-red, whilst the female is clouded with brown and
grey, with the red about her much less vivid than in the male. (15.
Mr. Ch. Fraser, in Proc. Zoolog. Soc. 1869, p. 3. I am indebted to
Mr. Bate for Dr. Power s statement.) In this case, we may suspect the
agency of sexual selection. From M. Bert s observations on Daphnia,
when placed in a vessel illuminated by a prism, we have reason to
believe that even the lowest crustaceans can distinguish colours. With
Saphirina (an oceanic genus of Entomostraca), the males are furnished
with minute shields or cell-like bodies, which exhibit beautiful
changing colours; these are absent in the females, and in both sexes of
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