在硬骨鱼类的腹腔内,几乎都有鳔。鱼鳔产生的浮力,使鱼在静止状态时,能自由控制身体处在某一水层。此外,鱼鳔还能使鱼腹腔产生足够的空间,保护其内脏器官,避免水压过大,内脏器官受损。因此,可以说鱼鳔掌握着鱼的生死存亡。可有一种鱼却是惊世骇俗的异类,它天生就没有鳔。神奇的是,它早在恐龙出现前三亿年前就已经存在地球上,至今已超过四亿年,它在近一亿年来几乎没 In the bony fishes abdominal cavity, almost all 鳔. Buoyancy buoyancy, the fish in the quiescent state, are free to control the body in a water layer. In addition, the fish 鳔 also make the abdominal cavity of the fish enough space to protect their internal organs, to avoid excessive water pressure, internal organ damage. Therefore, it can be said that fish hold the life and death of fish. There may be a fish is a strange alien, it is not born 鳔. The magic is that it existed on Earth for as long as 300 million years ago before the advent of the dinosaurs, so far it has exceeded 400 million years. It hardly has been in nearly 100 million years