蜗牛是一种陆地上有害的软体动物。正因为它对农业上有害处,所以我们要研究它、注意它,以消灭它。同时在软体动物肺螺目中它是一个很好的例子。在讲授蜗牛一节时,最好能捕捉一些活蜗牛来作为教具,可以观察它的运动方式及能伸缩的触角及小眼。但春季气候有时是比较冷的,在讲蜗牛一节时要找活的蜗牛作为教具是很困难的。为了补救这一缺点,我 Snail is a harmful mollusc on land. Just because it is agriculturally harmful, we have to study it, pay attention to it, and destroy it. It is also a good example of this in Mollusca. When teaching a Snail section, it is best to catch some live snails as a teaching aid to observe its movement patterns and retractable antennae and small eyes. However, the spring climate is sometimes colder, and it is very difficult to find living snails as teaching aids when talking about snails. In order to remedy this shortcoming, I