The paralytic shellfish poison of the giant sea scallop,Placopecten magellanicus(Gmelin), from the Bay of Fundy has been analyzed. Of eight toxins isolated, seven were identified with those previously recognized in various sources including the Atlantic toxic dinoflagellate,Gonyaulax tamarensiscells. The major components were gonyautoxin-I, gonyautoxin-II, and neosaxitoxin; saxitoxin was responsible for only a very small portion of the total toxicity. A minor toxin that was eluted between neosaxitoxin and saxitoxin in the chromatography system was found to be new and designated as gonyautoxin-VII.Key words: paralytic shellfish poisons, gonyautoxins, neosaxitoxin,Gonyaulax tamarensis