In wild-type worms, expression of
cat-2::gfp reporters was restricted to the 14 cells previously identified by a formaldehyde-induced fluorescence (FIF) assay for DA(CEPd, CEPv, ADE, PDE, R5A, R7A, R9A), plus 4 additional male-specific FIF-positive cells identified here for the first time. These are the four socket cells of the spicules.