title: Erratum.
abstract: In the report "Prenatal exposure to carbon monoxide: Learning and memory deficits" by C. F. Mactutus and L. D. Fechter (27 Jan., p. 409), the second sentence of the second full paragraph in column 3 of page 410 should have read, "A 2 by 2 analysis of covariance on the number of avoidance responses with covariates of number of avoidance responses in acquisition and number of adaptation and intertrial responses during reacquisition revealed significant effects of training contingency [F( 1, 57) = 23.8, P < 0.001] and an interaction of CO exposure with training contingency [F(1, 57) = 7.6, P < 0.008].