Fig. 80.—COMMON GARDEN SNAIL.
1308. Why is the shell spiral?
Partly because of its original formation; but also because, as the shell grows, the opening is elongated; and thrown up, causing the spiral body of the shell to turn, and so to wind its growth around the centre.
"Notwithstanding they hearkened not unto Moses; but some of them left it until the morning, and it bred worms, and stank: and Moses was wrath with them."—Exodus xvi.
1309. Why has the snail four tentacula attached to its head?
Because the insect, having no other limbs, is provided with those projecting members, the lower two serving as feelers and the upper two also as feelers and eyes. These, projecting in the front of the animal, impart to it a consciousness of surrounding objects, and especially of those which lie in its path.