Among the stars whose spectra show bands of the molecule C2, there exist a number in whose spectra the hydrogen lines are abnormally weak or absent. These stars are of two types: the first consists of the variable stars of the R Cr13 class, while the second consists of stars of somewhat similar spectrum which have not yet been found to be variable. lIigh4evel lines of C I have long been known to be present in the spectrum of R Cr13; a recent study of the visual region of the spectrum of that star at McDonald has shown that unusually strong high4evel lines of 0 1 and N I are also present. It is pointed out that the stars with abnormally weak hydrogen lines which have strong bands of C2 show little or no evidence of the carbon isotope of mass 13; this contrasts with the ratio of C12: C13 of the order of 3:1 which McKellar has found to be common to the normal carbon stars. Two features in the spectrum of the R CrB variable star SV Sge are identified with "tail" bands of the Swan system of C2.