Of those species which dwell upon the land and breathe the air, most affect moist situations. The common Garden Snail, as is well known, retires to crevices and corners in continued dry weather, where it closes its shell with a temporary door to prevent the evaporation of its vital juices, and patiently waits the return of congenial humidity. The first shower prompts the sensitive creatures to venture abroad, and we see them crawling by dozens over our borders and garden walks, imbibing from the steaming surface the grateful moisture. The damp woods of warm countries are the situations which most reward the researches of the laborious collector of land-shells; but there are some which are found in the driest places, as stony plains, and the summits of arid hills.
Many terrestrial Mollusca which ordinarily inhabit moist places, are enabled, by a precaution similar to that adopted by our own Snail in