HISTOLOGY AND REBUILDING OF THE BRAIN STEM FOR THE MANDARIN FISH SINIPERCA CHUATSI (BASILEWSKY)

The five brain stems of the mandar in fish, Siniperca chuatsi, were examined by means of silver－impregnation methylene-blue and H.E staining. There are centers of nine pairs of cranial nerves except the first pair of oranial nerve in the bain stem. Their sensory centers were generally located in the dorsal areas of the bain stem, and the motorial centers in the ventral areas. According to the areas occupied by the centers, the optic tectum is the first then the cerebello－acoustico－lateral center－octavus nuclei; the vagal lobes and ambiguous nuclei are the third. Although the seventh nuclei do not stick out and form the facial lobe the area held by the seventh nuclei was widely located in the lateral wall of the Ⅳ ventricle. The features of the mandarin fish＇s brain stem are of significance to its predation habit.