case formerly mentioned of lime-leaves) than could enter them. On other
occasions, however, they behaved very differently; for as soon as they
touched the base of a pine-leaf, this was seized, being sometimes
completely engulfed in their mouths, or a point very near the base was
seized, and the leaf was then quickly dragged or rather jerked into their
burrows. It appeared both to my son and myself as if the worms instantly
perceived as soon as they had seized a leaf in the proper manner. Nine
such cases were observed, but in one of them the worm failed to drag the
leaf into its burrow, as it was entangled by other leaves lying near. In
another case a leaf stood nearly upright with the points of the needles
partly inserted into a burrow, but how placed there was not seen; and
then the worm reared itself up and seized the base, which was dragged
into the mouth of the burrow by bowing the whole leaf. On the other
hand, after a worm had seized the base of a leaf, this was on two
occasions relinquished from some unknown motive.
As already remarked, the habit of plugging up the mouths of the burrows
with various objects, is no doubt instinctive in worms; and a very young
one, born in one of my pots, dragged for some little distance a
Scotch-fir leaf, one needle of which was as long and almost as thick as
its own body. No species of pine is endemic in this part of England, it
is therefore incredible that the proper manner of dragging pine-leaves
into the burrows can be instinctive with our worms. But as the worms on
which the above observations were made, were dug up beneath or near some
pines, which had been planted there about forty years, it was desirable
to prove that their actions were not instinctive. Accordingly,
pine-leaves were scattered on the ground in places far removed from any
pine-tree, and 90 of them were drawn into the burrows by their bases.
Only two were drawn in by the tips of the needles, and these were not
real exceptions, as one was drawn in for a very short distance, and the
two needles of the other cohered. Other pine-leaves were given to worms
kept in pots in a warm room, and here the result was different; for out
of 42 leaves drawn into the burrows, no less than 16 were drawn in by the
tips of the needles. These worms, however, worked in a careless or
slovenly manner; for the leaves were often drawn in to only a small
depth; sometimes they were merely heaped over the mouths of the burrows,
and sometimes none were drawn in. I believe that this carelessness may
be accounted for either by the warmth of the air, or by its dampness, as
the pots were covered by glass plates; the worms consequently did not
care about plugging up their holes effectually. Pots tenanted by worms
35