1. Peptide fingerprints of tryptic digests of the globins of sea snake species of Hydrophis, Pelamis, Aipysurus, Laticauda and the terrestrial elapid Naja were compared. 2. Globin divergence, as estimated from peptide fingerprints, paralleled closely transferrin divergence, as measured immunologically. 3. Taxonomic affinities, suggested by the fingerprint data, are concordant with McDowell's taxonomic system for sea snakes with the following exceptions: (a) Laticauda shows a closer affinity to the true sea snakes than to the terrestrial elapid Naja. (b) Sea snakes appear to be more widely divergent from terrestrial elapids than his scheme suggests.