[Free amino acids of hemolymph of marine isopods, Sphaeroma hookers Sphaeroma serratum (Flabellifera) and Idotea balthica (Valvifera)].

The total concentration of the free amino acids in the hemolymph is higher (about twice the amount in three species of marine Isopods (Sphaeroma hookeri, S. serratum and Idotea balthica) than in Decapods. In the three species so far studied, the proportions of glycine and taurine are always rather high. In the Sphaeromatidae, serine is the most concentrated amino acid while the proline concentration is comparatively low. The situation is reversed in Idotea balthica. In Crustaceans, the free amino acid composition of the hemolymph thus appears, both quantitatively and qualitatively, to be a biochemical character of marine Isopods when compared to Oniscoids Isopods and to Decapods.