Presents a study in which the phenotypic reversion of the rubber-band, muscle-defective phenotype conferred by unc-93(e1500) was used to determine the utility of N-ethyl-N-nitrosourea (ENU) as a mutagen for genetic research in Caenorhabditis elegans. What gene identity of 154 ENU-induced revertants indicates; Percentage of the frequency of ENU-induced intragenic deletions.