The Extra-Haemolymph Sodium of Asellus Aquaticus (L.)

Abstract

1. Some 20-30% of the total body sodium of the freshwater isopod Asellus aquaticus is not in the haemolymph. 2. Autoradiography shows that most of this sodium is not uniformly distributed in the tissues but is localized in the cells of Zenker's organ with lesser amounts in the ovaries, digestive tubules and cuticle. 3. Uric acid is also present in the cells of Zenker's organ. 4. No evidence is yet available to suggest the function of the sodium in the cells of Zenker's organ.