Abstract
Scharrer (1928) first described the function of neurosecretion in the nucleus preopticus of the hypothalamus of Phoxinus Laevis concerning the morphology of the nucleus preopticus of fishes. Later Palay (1945) reported that there is a topographical relation between the nucleus preopticus and the neurohypophysis in fishes (Catfishes, Ameriurus nebulosus, Ameriurus melas, Noturus flavus). This finding is supported by Hild (1951). Many researches on the hypothalamic neurosecretory system in fishes have been done by light microscopy (Scharrer, 1930, 1932, 1636, 1952, ; Florentin, 1934; Mazzi, 1941; Stutinsky, 1953; Bargmann, 1953, ; Stahl, 1953; Enami, 1954, 1955, Kobayashi et al., 1960; Szabo et al., 1965; Sathyanesan, 1966). While electron microscopic studies on the hypothalamic neurosecretory system in fishes have been reported by Palay (1960, goldfish), Lederis (1960, cod), Follenius (1963, truite, perche), and others. Hitherto we have examined, in the light of comparative anatomy, the neurosecretory cell of the hypothalamus in mammals, reptiles, and amphibians with the electron microscope (Murakami, 1962, 1963, 1964). Thus this paper will present the neurosecretory cell of the hypothalamus in fishes.
