《荀子·劝学》
螃蟹有六条腿，两个蟹钳，但是没有蛇、鳝的洞穴它就无处藏身，这是因为它用心浮躁。
蟹六跪而二螯，非蛇蟺之穴无可寄托者，用心躁也。
Crabs have six legs and two claws, yet without a burrow like a snake or eel, they have nowhere to hide, because they are inconstant.