King. Near Nice large castings abound in extraordinary
numbers, so that 5 or 6 were often found within the space of a
square foot. They consist of fine, pale-coloured earth, containing
calcareous matter, which after having passed through the bodies of
worms and being dried, coheres with considerable force. I have
reason to believe that these castings had been formed by species of
Perichaeta, which have been naturalized here from the East. {38}
They rise like towers, with their summits often a little broader
than their bases, sometimes to a height of above 3 and often to a
height of 2.5 inches. The tallest of those which were measured was
3.3 inches in height and 1 inch in diameter. A small cylindrical
passage runs up the centre of each tower, through which the worm
ascends to eject the earth which it has swallowed, and thus to add
to its height. A structure of this kind would not allow leaves
being easily dragged from the surrounding ground into the burrows;
and Dr. King, who looked carefully, never saw even a fragment of a
leaf thus drawn in. Nor could any trace be discovered of the worms
having crawled down the exterior surfaces of the towers in search
of leaves; and had they done so, tracks would almost certainly have
been left on the upper part whilst it remained soft.
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