蚯蚓没有眼睛。可是,蚯蚓却能感觉到光的明暗,如果把它放在有小孔的盒子里,几小时以后,它就从孔逃走了。原来,蚯蚓的身体表面到处都有感光细胞,尤其身体前端的口器上的感光细胞特别多。这些感光细胞就有眼睛的作用,能感觉到光的存在,以及辨别光的强弱。蚯蚓不喜欢阳光,大部分时间在地下,夜间才钻出地面来活动。 Earthworms have no eyes. However, the earthworm can feel the light and shade, if you put it in a box with holes, a few hours later, it escaped from the hole. It turned out that the surface of earthworms have photoreceptor cells everywhere, especially the front of the mouth of the body of photoreceptor cells in particular. These photoreceptor cells have the function of eyes, the presence of light, and the discrimination of light intensity. Earthworms do not like sunlight, most of the time in the ground, night before drilling out of the ground to activities.