Résumé : Results are presented on the {Mathematical expression} values of hypernuclei in the mass range A=3 to A=12 obtained from a sample of 595 uniquely identified π--mesonic decays. The problems of what constitute adequate selection criteria for the unique identification of an event are discussed. The disagreement between the {Mathematical expression} values obtained from different decay modes of {Mathematical expression} indicates a possible error in the range-energy relationship. © 1966 Società Italiana di Fisica.