Trochus pyramis Born is of gonophores.The male reproductive system is mainly composed of the spermaries and spermaductus, instead of mating and others glands.

摘要塔形马蹄螺为雌异，其殖系统主要由精巢和输精管组成，没有交器，也没有其他附属腺。

4 Turbellarians are monoecious with the reproductive systems adapted for internal fertilization. And the monogenetic flukes (class Monogenea) are mostly ectoparasites of fishes.

涡虫是雌同，殖系统适于内受精。单起源吸虫（单殖纲）大多是鱼外寄虫。