the base. This again indicates that the result is not determined by
chance. Worms appear sometimes to revolve in the act of drawing in the
triangles, for five out of the whole lot had been wound into an irregular
spire round the inside of the burrow. Worms kept in a warm room drew 63
triangles into their burrows; but, as in the case of the pine-leaves,
they worked in a rather careless manner, for only 44 per cent. were drawn
in by the apex, 22 per cent. by the middle, and 33 per cent. by the base.
In five cases, two triangles were drawn into the same burrow.
It may be suggested with much apparent probability that so large a
proportion of the triangles were drawn in by the apex, not from the worms
having selected this end as the most convenient for the purpose, but from
having first tried in other ways and failed. This notion was
countenanced by the manner in which worms in confinement were seen to
drag about and drop the triangles; but then they were working carelessly.
I did not at first perceive the importance of this subject, but merely
noticed that the bases of those triangles which had been drawn in by the
apex, were generally clean and not crumpled. The subject was afterwards
attended to carefully. In the first place several triangles which had
been drawn in by the basal angles, or by the base, or a little above the
base, and which were thus much crumpled and dirtied, were left for some
hours in water and were then well shaken while immersed; but neither the
dirt nor the creases were thus removed. Only slight creases could be
obliterated, even by pulling the wet triangles several times through my
fingers. Owing to the slime from the worms bodies, the dirt was not
easily washed off. We may therefore conclude that if a triangle, before
being dragged in by the apex, had been dragged into a burrow by its base
with even a slight degree of force, the basal part would long retain its
creases and remain dirty. The condition of 89 triangles (65 narrow and
24 broad ones), which had been drawn in by the apex, was observed; and
the bases of only 7 of them were at all creased, being at the same time
generally dirty. Of the 82 uncreased triangles, 14 were dirty at the
base; but it does not follow from this fact that these had first been
dragged towards the burrows by their bases; for the worms sometimes
covered large portions of the triangles with slime, and these when
dragged by the apex over the ground would be dirtied; and during rainy
weather, the triangles were often dirtied over one whole side or over
both sides. If the worms had dragged the triangles to the mouths of
their burrows by their bases, as often as by their apices, and had then
perceived, without actually trying to draw them into the burrow, that the
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