Examinations were made on the nonphenolic tertiary bases in the rhizome of Corydalis ambigua CHAM. et SCHLECHT. var. amurensis MAXIM. (Japanese name, Ezoengosaku) and base (‡Y), C26H21O4N, m.p. 171•`172•‹, (possibly sinactine), and dl-tetrahydropalmatine were isolated. Presence of canadine was suggested from the result of thin-layer chromatography. Base (I), isolated earlier, was identified by mixed fusion with d-corybulbin, kindly supplied by Dr. Manske. Examinations were also made on quaternary bases in this rhizome and dehydrocorybulbine, dehydrobase (‡U), dehydrocorydaline, and palmatine were isolated as the protoberberine-type bases. All the alkaloids found in the rhizome of Corydalis ambigua CHAM. et SCHLECHT. var. amurensis MAXIM, are listed in Table I.(Received February 24, 1964)