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burrows are not gnawed。 I have seen as many as nine leaves of the
lime…tree drawn into the same burrow； and not nearly all of them
had been gnawed； but such leaves may serve as a store for future
consumption。 Where fallen leaves are abundant； many more are
sometimes collected over the mouth of a burrow than can be used； so
that a small pile of unused leaves is left like a roof over those
which have been partly dragged in。
A leaf in being dragged a little way into a cylindrical burrow is
necessarily much folded or crumpled。 When another leaf is drawn
in； this is done exteriorly to the first one； and so on with the
succeeding leaves； and finally all become closely folded and
pressed together。 Sometimes the worm enlarges the mouth of its
burrow； or makes a fresh one close by； so as to draw in a still
larger number of leaves。 They often or generally fill up the
interstices between the drawn…in leaves with moist viscid earth
ejected from their bodies； and thus the mouths of the burrows are
securely plugged。 Hundreds of such plugged burrows may be seen in
many places； especially during the autumnal and early winter
months。 But； as will hereafter be shown； leaves are dragged into
the burrows not only for plugging them up and for food； but for the
sake of lining the upper part or mouth。
When worms cannot obtain leaves； petioles； sticks； &c。； with which
to plug up the mouths of their burrows； they often protect them by
little heaps of stones； and such heaps of smooth rounded pebbles
may frequently be seen on gravel…walks。 Here there can be no
question about food。 A lady； who was interested in the habits of
worms； removed the little heaps of stones from the mouths of
several burrows and cleared the surface of the ground for some
inches all round。 She went out on the following night with a
lantern； and saw the worms with their tails fixed in their burrows；
dragging the stones inwards by the aid of their mouths； no doubt by
suction。 〃After two nights some of the holes had 8 or 9 small
stones over them； after four nights one had about 30； and another
34 stones。〃 ｛29｝ One stonewhich had been dragged over the
gravel…walk to the mouth of a burrow weighed two ounces； and this
proves how strong worms are。 But they show greater strength in
sometimes displacing stones in a well…trodden gravel…walk； that
they do so； may be inferred from the cavities left by the displaced
stones being exactly filled by those lying over the mouths of
adjoining burrows； as I have myself observed。
Work of this kind is usually performed during the night； but I have
occasionally known objects to be drawn into the burrows during the
day。 What advantage the worms derive from plugging up the mouths
of their burrows with leaves； &c。； or from piling stones over them；
is doubtful。 They do not act in this manner at the times when they
eject much earth from their burrows； for their castings then serve
to cover the mouths。 When gardeners wish to kill worms on a lawn；
it is necessary first to brush or rake away the castings from the
surface； in order that the lime…water may enter the burrows。 ｛30｝
It might be inferred from this fact that the mouths are plugged up
with leaves； &c。； to prevent the entrance of water during heavy
rain； but it may be urged against this view that a few； loose；
well…rounded stones are ill…adapted to keep out water。 I have
moreover seen many burrows in the perpendicularly cut turf…edgings
to gravel…walks； into which water could hardly flow； as well
plugged as burrows on a level surface。 It is not probable that the
plugs or piles of stones serve to conceal the burrows from
scolopendras； which； according to Hoffmeister； ｛31｝ are the
bitterest enemies of worms； or from the larger species of Carabus
and Staphylinus which attack them ferociously； for these animals
are nocturnal； and the burrows are opened at night。 May not worms
when the mouth of the burrow is protected be able to remain with
safety with their heads close to it； which we know that they like
to do； but which costs so many of them their lives？ Or may not the
plugs check the free ingress of the lowest stratum of air； when
chilled by radiation at night； from the surrounding ground and
herbage？ I am inclined to believe in this latter view： firstly；
because when worms were kept in pots in a room with a fire； in
which case cold air could not enter the burrows； they plugged them
up in a slovenly manner； and secondarily； because they often coat
the upper part of their burrows with leaves； apparently to prevent
their bodies from coming into close contact with the cold damp
earth。 Mr。 E。 Parfitt has suggested to me that the mouths of the
burrows are closed in order that the air within them may be kept
thoroughly damp； and this seems the most probable explanation of
the habit。 But the plugging…up process may serve for all the above
purposes。
Whatever the motive may be； it appears that worms much dislike
leaving the mouths of their burrows open。 Nevertheless they will
reopen them at night； whether or not they can afterwards close
them。 Numerous open burrows may be seen on recently…dug ground；
for in this case the worms eject their castings in cavities left in
the ground； or in the old burrows instead of piling them over the
mouths of their burrows； and they cannot collect objects on the
surface by which the mouths might be protected。 So again on a
recently disinterred pavement of a Roman villa at Abinger
（hereafter to be described） the worms pertinaciously opened their
burrows almost every night； when these had been closed by being
trampled on； although they were rarely able to find a few minute
stones wherewith to protect them。
Intelligence shown by worms in their manner of plugging up their
burrows。If a man had to plug up a small cylindrical hole； with
such objects as leaves； petioles or twigs； he would drag or push
them in by their pointed ends； but if these objects were very thin
relatively to the size of the hole； he would probably insert some
by their thicker or broader ends。 The guide in his case would be
intelligence。 It seemed therefore worth while to observe carefully
how worms dragged leaves into their burrows； whether by their tips
or bases or middle parts。 It seemed more especially desirable to
do this in the case of plants not natives to our country； for
although the habit of dragging leaves into their burrows is
undoubtedly instinctive with worms； yet instinct could not tell
them how to act in the case of leaves about which their progenitors
knew nothing。 If； moreover； worms acted solely through instinct or
an unvarying inherited impulse； they would draw all kinds of leaves
into their burrows in the same manner。 If they have no such
definite instinct； we might expect that chance would determine
whether the tip； base or middle was seized。 If both these
alternatives are excluded； intelligence alone is left； unless the
worm in each case first tries many different methods； and follows
that alone which proves possible or the most easy； but to ac