There is reason, too, for winged creatures having feet, but fish none.The former have their home in the dry medium, and cannot remain always in mid air; they must therefore have feet.Fish on the contrary live in the wet medium, and take in water, not air.Fins are useful for swimming, but feet not.And if they had both they would be non-sanguineous.There is a broad similarity between birds and fishes in the organs of locomotion.Birds have their wings on the superior part, similarly fish have two pectoral fins; again, birds have legs on their under parts and near the wings; similarly, most fish have two fins on the under parts and near the pectorals.Birds, too, have a tail and fish a tail-fin.
同类推荐
热门推荐
我家主人才没那么可爱
新世纪女仆三定律：第一、服从少爷的一切命令。那包括那些色色、不能说的，潜规则的咩？第二、遵从少爷的一切喜好。那挑什么样的男人嫁也要被他插手咩？第三、绝对不准爱上少爷。哦，三条看起来，最后一条最简单了。像这种阴晴不定，喜怒无常，还命令小女仆和自己玩一年契约婚姻的家伙有什么好爱上的。
