But now the tide has reached its lowest mark; and as we wander over
the wet sand at its very verge, our attention is attracted by every
tiny object that breaks the uniform level, even at a considerable
distance. Some of these are worm-casts thrown up by busy Annelids,
working away in the sand to reach a lower and therefore a wetter level,
as the upper stratum dries in the sun. But others are Crabs, of two or
three species. One of them is the somewhat uncommon and very beautiful
_Portumnus variegatus_, of which a great number are left by the sea,
but all of them dead; some of them, however, from their freshness,
only recently defunct. The shape of the carapace, or body-shell, is
very elegant, and the colours, though sober--a light drab, mottled and
pencilled with pale lilac--are pleasing: the hindmost pair of feet
terminate in thin swimming-plates, but they are narrow, and exhibit the
natatory character in only a subordinate degree.
Other Crabs are alive and active, though, to be sure, in a somewhat
sluggish way. Here we catch sight of a slight movement in the wet
sand, and, stooping, we perceive a pair of antennæ, much beset with
short bristles, projecting from the surface. They wag to and fro,
and presently up pushes a shelly head, with its pair of stalked and
jointed eyes, and two tremendously long angular arms, furnished with
awkward-looking nippers at their extremities. Another effort, and
the whole Crab emerges from his sandy burrow, and displays his pale
buff-coloured shell, wrinkled across, and armed with sharp spiny points
at its front and edges. We easily take him up, for his means of escape
are feeble, as he uncouthly shuffles on his short legs over the sand;
and his bellicose instincts are not strongly developed, nor, if they
were, have those long levers of arms any formidable powers of offence.
Latreille gave to the genus the title of _Corystes_; which signifies a
warrior armed for battle, from κόρυς, a helmet, but its inoffensiveness
belies the appellation.[62] Pennant had already conferred on the
species the name of _Cassivelaunus_, the ancient British chief
immortalized by Cæsar. If you were to ask me why this obscure crab
should bear a name so renowned, I can answer only by conjecture. The
carapace is marked by wrinkles, which, while in some specimens they
suggest nothing, in others, especially old males, bear the strongest
and most ludicrous resemblance to the face of an ancient man. I have
taken specimens in which the _vraisemblance_ was so perfect as to
strike me, and others to whom I showed it, with amazement. Now Pennant,
as is well known, had strong sympathies with his British ancestry;
and perhaps, by a not extravagant stretch of imagination, his playful
fancy saw the features of the grand old Celtic warrior perpetuated on
this Crab, which he first met with, too, be it remembered, on the Welsh
coast.
[Illustration: