title: Erratum.
abstract: In the report by C. W. McCutchen [197, 691 (1977)], the sentence in paragraph 2, column 3, "The downward motion is an inversion of the upward motion about a point on the axis of samara spin" is in error. It should be replaced by "The downward motion is a reflection of the upward motion successively in a horizontal and in a vertical plane."