Biochemical studies on the enteropneust Balanoglossus gigas (Fr. Muller, 1898)

1. 1. The water, sodium, potassium, chloride, calcium, magnesium, phosphorus, total sulphur, inorganic sulphur, copper, iron, iodine and nitrogen contents of the proboscis, collar, branchial, genital, hepatic and intestinal regions of the enteropneust Balanoglossus gigas (Fr. Muller) were determined. 2. 2. The chemical constitution of the mucus, faeces and skeleton was also determined. 3. 3. Iodine is accumulated in the dorsal side of the hepatic region, iron in the hepatic region, sulphur in the sub-region hepatic II, nitrogen in the genital and hepatic regions, chloride in the collar and branchial region, copper in the collar, phosphorus in the proboscis and hepatic region; sodium, calcium, potassium and magnesium are concentrated both at the anterior and posterior end of the animal. 4. 4. The skeleton has high concentrations of calcium and copper.