Antennular chemosensitivity in the spiny lobster,Panulirus argus,to extract of the pink shrimp,Penaeus duorarumis based on extract components of less than 1,000 molecular weight. Amino acids account for a major part, but not all, of the extract's capacity to stimulate antennular receptors. Taurine is the most stimulatory of the amino acids comprisingP. duorarumextract, although no single amino acid accounts for the amino acid fraction's stimulatory potential.