Non-protein amino acids in muscle and blood of marine and fresh water Crustacea.

Muscle and other tissues of marine invertebrates are very dilute with respect to inorganic ions, but are nevertheless in osmotic equilibrium with the blood, in which ionic concentrations are nearly the same as in sea water (1). It has been postulated, therefore, that these tissues contain relatively high concentrations of small organic molecules (l), and it is of interest in this connection that considerable quantities of glycine (2) and taurine (3-5) have been found in tissues of various marine invertebrates. Fifteen amino acids have now been determined in muscle of both marine and fresh water Crustacea.