a1 Department of Anatomy, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
a2 Biology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
Adult males of Schistosoma mansoni were preincubated in 5-hydroxtryptamine (5HT) and processed through the glyoxylic acid fluorescence technique to visualize 5HT-containing neural elements. 5HT flourescence was seen as a series of cross-sectional rings beginning behind the ventral sucker toward the tail end. The rings were connected by two lateral nerve cords running longitudinally along the whole lenght of the worms.
(Accepted July 16 1980)