--Although worms usually live near the surface, yet they
burrow to a considerable depth during long-continued dry weather
and severe cold. In Scandinavia, according to Eisen, and in
Scotland, according to Mr. Lindsay Carnagie, the burrows run down
to a depth of from 7 to 8 feet; in North Germany, according to
Hoffmeister, from 6 to 8 feet, but Hensen says, from 3 to 6 feet.
This latter observer has seen worms frozen at a depth of 1.5 feet
beneath the surface. I have not myself had many opportunities for
observation, but I have often met with worms at depths of 3 to 4
feet. In a bed of fine sand overlying the chalk, which had never
been disturbed, a worm was cut into two at 55 inches, and another
was found here at Down in December at the bottom of its burrow, at
61 inches beneath the surface. Lastly, in earth near an old Roman
Villa, which had not been disturbed for many centuries, a worm was
met with at a depth of 66 inches; and this was in the middle of
August.
The burrows run down perpendicularly, or more commonly a little
obliquely. They are said sometimes to branch, but as far as I have
seen this does not occur, except in recently dug ground and near
the surface. They are generally, or as I believe invariably, lined
with a thin layer of fine, dark-coloured earth voided by the worms;
so that they must at first be made a little wider than their
ultimate diameter.
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