w the eighth segment, or rather below the
strip of membrane separating this segment and the last, we see two
spikes, slightly curved, short, but with strong, sharp, hard points,
and placed one to the right and the other to the left of the median
line. These two appendages are able, by means of a mechanism
recalling, on a smaller scale, that of the Snail's horns, to withdraw
into themselves, as a result of the membranous character of their
base. They can also retreat under the eighth segment, borne, as they
are, by the anal segment, when this last, as it contracts, withdraws
into the eighth. Lastly, the ninth or anal segment bears on its hinder
edge two long cirri, like those of the legs and the antennae, curving
backwards from tip to base. At the rear of this segment a fleshy
nipple appears, more or less prominent; this is the anus. I do not
know where the stigmata are placed; they have evaded my
investigations, though these were undertaken with the aid of the
microscope.

When the larva is at rest, the various segments overlap evenly; and
the membranous intervals, corresponding with the articulations, do not
show. But, when the larva walks, all the articulations, especially
those of the abdominal segments, are distended and end by occupying
almost as much space as the horny arches. At the same time the anal
segment emerges from the sheath formed by the eighth; the anus, in
turn, is stretched into a nipple; and the two points of the
penultimate ring rise, at first slowly, and then suddenly stand up
with an abrupt motion similar to that of a spring when released. In
the end, these two points diverge like the horns of a crescent. Once
this complex apparatus is unfolded, the tiny creature is ready to
crawl upon the most slippery surface.

The last segment and its anal button are curved at right angles to the
axis of the body; and the anus comes and presses upon the surface of
locomotion, where it ejects a tiny drop of transparent, treacly fluid,
which glues and holds the little creature firmly in position,
supported on a sort of tripod formed by the anal button and the two
cirri of the last segment. If we are observing the animal's manner of
locomotion on a strip of glass, we can hold the strip in a vertical
position, or even turn it upside down, or shake it lightly, without
causing the larva to become detached and fall, held fast as it is by
the glutinous secretion of the anal button.

If it has to proceed along a sur