1) The testis of Sebastes inermis were collected monthly, measured their weight and observed their seasonal histological change. 2) The weight (Gonad Index) of the testis of Sebastes inermis increased since October, in November its augmentation was rapidly and it indicated the highest value, but afterwards it decreased with the gentle slope and showed the lowest value between April and August. The hesviest month of the testis weight coincided with the highest month of the spermatogenesis, the period of the copulation did not coincided with the heaviest month of the testis weight and was next month of it. 3) The stage of the testis maturity could be divided into four categories from the histological observation, that is 1, The preparative period for the spermatogenesis………………………July-September 2, The period of the spermatogenesis………………………………………October-November 3, The discharging period of the spermium (The period of the copulation)-December 4, The resting period………………………………………………………………… January-June. 4) The mesonephric duct of Sebastes inermis was shorter than that in Sebastiscus spp. The fore part of the testis was consisted of the sperm-storerooms which a mesonephric duct divided with the branches and there was no seminiferous tubule in that part. Having the sperm-storeroom, the period of the spermatogenesis in Sebastes inermis is longer than that in Sebastiscus marmoratus. 5) The inner wall of the sperm-storeroom was consisted of the simple columnar epithelium which have many tufts at the surface. 6) In the last stage of the spermatogenesis, the secretion was excreted to the seminiferous tubule with the spermium when the cyst broke out. 7) This secretion was dyed by eosin, and it was the substance for support and supply of the nutriment to spermium. This substance remained in the mesonephric duct and the sperm-storerooms for five monthes after the copulation, therefore the weight of the testis was not decreased rapidly. 8) The abnormal spermatogenesis was seen here and there in the seminiferous tubule for six monthes after the copulation, and it seemed that the duration of abnormal spermatogenesis was the resting period of the testis. 9) The testis of tubular type, the origin of the spermatogonia, the process of the spermatogenesis, the condition and mision or the prosperity and decay of the seminiferous epithelium and the existence or rise and fall of the interstitial cell etc. were the same to Sebastiscus marmoratus.

1)メバルの精巣を毎月採集しそれ等の重量測定を行い組織切片を作製してその季節的変化を観察した。2)精巣の重量測定の結果(生殖腺成熟度指数),メバルにおいては精巣は10月からその重量が増加し,1月に急増して最高値を示すがその後は次第に値は減少する。4月―8月は特にその値は低い。精巣重量最高の時期は精子形成の最盛期と一致する。精虫放出(交尾)の時期は精巣重量最高の時期ではなくてその次の時期である。3)精巣の組織学的観察結果からその成熟状態を大別すると下の如くなる。1.7月―9月… … 精子形成の準備の時期 2.10月―11月… …精子形或の時期 3.12月…………… 精虫放出の時期(交尾) 4.1月―6月… …休止の時期 4)メバル精巣の交接器に近い部分は輸精管が枝分れしてできた貯精嚢を形成していて,その部分には精細管はない。メバルは貯精嚢を持っているので精子形成の期間はカサゴの場合より長い。この魚の輸精管はカサゴに比べて非常に短い。 5)貯精嚢の内壁の細胞は表面に長い束毛を持った円柱上皮から成る。6)精子形成の終りにCystが破れる時に精虫と共に分泌物が精細管内に出る。7)この分泌物質はEosinで染まり,精虫の支持又は栄養供給の物質であると思われる。この物質は交尾後相当長期間貯精嚢及び輸精管内に残る。その為精巣の重量は急には減少しない。8)交尾後精巣精細管内において可成り長期にわたってAbnormalな精子形成を行っているのが散見される。9)この魚の精巣がTubular typeである事,精原細胞の由来,精子形成の過程,精上皮細胞の状態とその使命及び消長,間質細胞の存在と消長等はカサゴの場合と全く同じである。

長崎大学水産学部研究報告, v.8, pp.111-122; 1959