Abstract
Arterio-arterio and arterio-venous vasculatures in the gills of eel Anguilla japonica, carp Cyprinus carpio, and yellowtail Seriola quinqueradiata were examined by resin-replica method. Their ampullae and anastomotic capillaries of secondary lamellae exhibited species differences in the structural features. In the infusion of resin into the eel gills for 2, 5, and 10 min, the replica of afferent companion vessels, central venous sinus, efferent companion vessel, and afferent artery was produced, but that of the capillaries in secondary lamellae and efferent artery was not recognizable. This finding suggests more abundant blood circulation in the arterio-venous vasculature than in the arterio-arterio one.