y.

A garment should be neither too short nor too tight. It is not enough
to add a piece which lengthens it as the body grows longer; we must
also see that it has sufficient fulness not to hamper the wearer and
to give him liberty of movement.

The Snail and all the molluscs with turbinate shells increase the
diameter of their corkscrew staircase by degrees, so that the last
whorl is always an exact measure of their actual condition. The lower
whorls, those of childhood, when they become too narrow, are not
abandoned, it is true; they become lumber-rooms in which the organs of
least importance to active life find shelter, drawn out into a slender
appendage. The essential portion of the animal is lodged in the upper
story, which increases in capacity.

The big Broken Bulimus, that lover of crumbling walls and limestone
rocks leaning in the sun, sacrifices the graces of symmetry to
utility. When the lower spirals are no longer wide enough, he abandons
them altogether and moves higher up, into the spacious staircase of
recent formation. He closes the occupied part with a stout
partition-wall at the back; then, dashing against the sharp stones, he
chips off the superfluous portion, the hovel not fit to live in. The
broken shell loses its accurate form in the process, but gains in
lightness.

The Clythra does not employ the Bulimus' method. It also disdains that
of our dressmakers, who split the overtight garment and let in a piece
of suitable width between the edges of the opening. To break the jar
when it becomes too small would be a wilful waste of material; to
split it lengthwise and increase its capacity by inserting a strip
would be an imprudent expedient, which would expose the occupant to
danger during the slow work of repair. The hermit of the jar can do
better than that. It knows how to enlarge its gown while leaving it,
except for its fulness, as it was before.

Its paradoxical method is this: of the lining it makes cloth, bringing
to the outside what was inside. Little by little, as the need makes
itself felt, the grub scrapes and strips the interior of its cell.
Reduced to a soft paste by means of a little putty furnished by the
intestine, the scrapings are applied over the whole of the outer
surface, down to the far end, which the grub, thanks to its perfect
flexibility, is able to reach without taking too much trouble or
leaving its house.

This turning of the coat is accomplished with a delicate preci