Abstract: The nervous system of Cotylophoron indicum was studied by using acetylcholine esterase histochemical staining techniques. Cranial ganglia and transverse commissure situate at dorso-lateral body between oral sucker and genital sucker. From the cranial ganglia four pairs of nerves proceed cephalad and connect with nerve network of the oral sucker. The posterior nerve cords from the cranial ganglia consist of 3 pairs and the ventral ones are the stoutest and longest nerves. A few branches from the 3 pairs of nerve cords connect to ventral sucker. There is a developed nerve network distributed in its genital sucker. The nerve fibers on body surface in pairs and parallel are diagonal and cross to form a nerve network on body surface. Three kinds of neurocytes distribute at the prosomal region. Results show that the nervous system structure of C. indicum is consistent with the essential features of Digenea， but more special and complicated around genital sucker.

Key words: Cotylophoron indicum, Nervous system, Acetylcholinesterase, Histochemistry