LAND SNAILS. 19 



to crawl, and then their resemblance to the shell-bearing 

 snails will be seen at once. 



Instead of having a coiled shell into which they can 

 retreat when alarmed, they have a little limy scale imbedded 

 in a portion of the back, called the mantle. The breathing- 

 orifice is on the right side of the body, and the tentacles, 

 mouth-parts, creeping disk, and other features, are quite 

 similar to the land snails already studied. 



a 



FIG. 22. A NAKED LAND SNAIL, OB SLUG, FULLY EXPANDED. a. Mantle ; &, Breathing- 

 Orifice. 



18. On the approach of winter, land snails bury them- 

 selves in the ground, and those that have shells retire within 

 the shell as far as possible, and close the aperture of the shell 

 with a film of the mucus which the body secretes so abun- 

 dantly. In this condition they remain dormant until the 

 warm weather of spring revives them again. 



If the pupil will collect a lot of snails in the early spring, 

 and keep them confined in a box, with earth, damp leaves, or 

 bits of rotten wood or bark, the snails in the course of a few 

 weeks will lay a number of little eggs. These eggs will be 

 white and round, about the size of a pin's-head. By careful 

 tending, that is, by keeping the leaves slightly moist, the 



