Studies on a Scorpaenous fish Sebastiscus marmoratus CUVIER et VALENCIENNS……II The Seasonal cycle of Mature Testis and the Spermatogenesis

摘要

1) The testis of Sebastiscus marmoratus is collected monthly and observed their seasonal histological change. 2) The histological condition of the testis can be divided into four categories, that is 1, The preparative period for the spermatogenesis……June～August 2, The period of the spermatogenesis……September 3, The discharging period of the spermium……October～The first decade of November. 4, The resting period……The middle decade of November～May. 3) The testis does not consist of lobules or cysts, but seminiferous tubules, namely, that is tubular-type testis. 4) There is the seminiferous epithelium inner surface of the seminiferous tubule and on the basement membrane. In June the spermatogonia appears from between the basement membrane and seminiferous epithelium. 5) After the appearance of the spermatogonia, the seminiferous epithelium serves as the nurse cell for the spermatogenesis, and it disappears when the spermatogenesis comes to end. There is no Sertoli's cell in the testis of the fish. 6) When the seminiferous tubule is filled by the spermium after spermatogenesis, the new seminiferous epithelium appears once more in single layer on the basement membrane. 7) The spermatogenesis is performed in a short time all together in September, and this is the heaviest time of the testis in all the year. 8) The sperm cell performs the syncytium, namely the nucleus of a spermatogonia produces the many spermatocytes by division which are comprised by a cyst, and the cysts disappear in the stage of spermium and the seminiferous tubule is filled by the spermium. 9) In later stages, in the spermatogenesis the sperm cells gradually decrease in size and become internally compact and more stainable by haematoxilin. 10) It is induced from the internal state of the seminiferous tubule that the time of copulation is between October and the first decade of November. 11) The abnorma lspermatogenesis is found at a few large fish in the resting period (in February) which is the poorest time of the testis and the ripest time of the ovary. 12) The spermium of this fish does not form the sperm ball or the bundle. 13) There is the interstitial cell between the seminiferous tubules at a certain period of a year as well as in the higher vertebrata. 14) There is no evidence which the interstitial cell of this fish has the endocrine function, but it is clear that the interstitial cell is closely related to the spermatogenesis from the viewpoint of its quantitative fluctuation.