Herdmania is a bisexual animal. It is a protogynous animal. Ovary matures’ first. Hence cross fertilization takes place.
Herdmania contains a pair of gonads. The left gonad lies in the intestinal loop above the heart. Each gonad shows 10 to 25 lobes arranged in two rows. The median lobe is single and large. Other lobes are oval in shape.
Each lobe shows outer large testicular part and inner small ovarian part. The testicular part is brick red in colour and produces sperms. The ovarian part is pink in colour and produce ova. From each testicular part sperm ductule will arise. They open into spermduct. From each ovarian part ovarian ductule will come. They open into the oviduct. Each gonad has an oviduct and spermduct. They run parallelly and open separately into cloaca behind anus.