脊椎动物皆有其正之脑,所帮其正者,即是其脑与无脊椎动物之“脑”不同;其脑之本身,分为五大部分,其中空腔,由前端達於后端,与脊髓之髓管相通,此文所言之鱼脑,即是如此。鱼类在所有脊椎动物之中位置最低,其脑亦较其他脊椎动物之脑为下等,鱼脑为高等脊椎动物之脑的雏型。由鱼类而上,如两棲类,爬行类,鸟类,哺乳类,以至人类:脑部逐步演进,哺乳类之脑已甚複杂,在人类尤甚。人脑构造之精密,为任何动物所不及,然眞脑之初步演化,在鱼脑见之。故研究鱼脑,为研究比较神经学者必循之步骤,猶之讀歷史须由上古开始。真脑之出现角类以下之动物,其较下等者无论已,即脊索动物之最高等者,頭索类(Cephalochorda),若海予(Amphioxus),尚无眞脑,唯至鱼类方始有眞脑。鱼脑之五部分皆全,高等脊椎动物之脑的基础即是 Vertebrates have their positive brain, to help its positive, that is, its brain and invertebrate “brain ” is different; its brain itself, is divided into five parts, including the cavity, up to the rear end of the front , And the medullary canal of the spinal cord interlinked, this article fish brain, that is the case. Fish is the lowest among all vertebrates and its brain is inferior to the brains of other vertebrates. The fish brain is the prototype of the higher vertebrate brain. From fish, such as amphibians, reptiles, birds, mammals and even humans: the gradual evolution of the brain, mammalian brain has been very complex, especially in humans. The structure of the human brain is sophisticated enough for any animal to catch. However, the initial evolution of the brain is seen in the fish brain. Therefore, the study of fish brain, neuroscientists to study the necessary steps to follow, still reading history should be from the beginning of the Middle Ages. The emergence of the brain below the horn angle of the animals, the lower, regardless of whether they have the highest, such as Chordates, Cephalochorda, if the sea to (Amphioxus), there is no brain, only until the beginning of the fish眞 brain. The five parts of the fish brain are all based on the brain of the higher vertebrates that is