Doses of puromycin or cycloheximide which prevent morphological transformation, following a temperature shift from 41 to 37°, of chick embryo cells infected with the ts mutant FU 19 of SR-RSV (D) do not prevent the increase of cell agglutinability by concanavalin A which normally parallels transformation. Hence, cell transformation and agglutinability may depend on the expression of distinct viral information; or, alternatively, they could depend on different levels of expression of the same information