The nematodeC. briggsaeis an excellent genetic model for comparative and evolutionary studies involving its well-known cousinC. elegans. The vulval system in these two species has been used extensively to investigate genes and pathways involved in cell proliferation and cell differentiation. Here we report initial characterization of twoC. briggsaemultivulva (Muv) mutants,Cbr-lin(bh1)andCbr-lin(bh3).