The male reproductive system of Oratosquilla kempi includes: testis, vas deferens, penis, and accessory sex gland. The duct..shaped testis, with a straight end, curves forward gradually and finally curls into a ear..like structure at the seventh and eighth thoraxmeron. The wall of vas deferens has no muscles. There is a stick..like penis at the base of the eighth thoraxmeron, and the join point, like a membrane, is soft enough to curve freely , but the free end is relatively hard with crust around. Between the fourth and seventh thoraxmeron, a pair of male accessory sex glands could be seen, like thin silk, and lef t and right ends reach penis paralleled by the same side vas deferens respectively. The testis cavity.. s tip is f illed with spermatid of different developmental stages which are gradually maturing from the tip to post.., mid.., and front..end testis, then to vas deferens and penis. The spermatid is egg.. shaped with thick membrance but without flagellum and acrosome, and its size is about 8. 5..m .. 7. 0..m.