And I find that several species in this state withstand uninjured an immersion in sea-water during seven days.

One shell, the Helix pomatia, after having been thus treated, and again hybernating, was put into sea-water for twenty days and perfectly recovered.

During this length of time the shell might have been carried by a marine country of average swiftness to a distance of 660 geographical miles.

As this Helix has a thick calcareous operculum I removed it, and when it had formed a new membranous one, I again immersed it for fourteen days in sea-water, and again it recovered and crawled away.