Abstract The uptake of the radioisotopes cadmium 115 M and zinc 65 confirm earlier studies on these metals. Within certain limits, the amount of metal previously taken up does not preclude the entry of more metal. The chelating agent, ethylene diamine tetracetic acid, tends to reduce the amount of these metals which enters the snail but to a different extent for each. About 62% of the initial metal taken up is retained after 48 hours, after the metal is removed from the environment, and the distribution of metal within the snail is about the same as it was initially. Autoradiographs show a high concentration of cadmium in liver, kidney and oviduct, but only part of the intestinal contents were radioactive, and there was little evidence of radioactivity in other structures.