Fig. 3. Ppa-pax-3 mutant animals are generation vulvaless. Nomarski photomicrographs of early (A,B) and late (C,D) stages of the vulva in P. pacificus wild-type (A,C) and Ppa-pax-3 mutant (B,D) animals. (A) P. pacificus wild-type animal in the early J3 stage showing P(5-8).p before the onset of cell divisions. (B) Ppa-pax-3 mutants in a similar developmental stage. P(5-8).p are absent. (C) P. pacificus wild-type animal in the mid J4 stage. A vulva has been formed. In this plane of focus, the progeny of the 2° cells P(5,7).p are visible. (D) Ppa-pax-3 mutants in a similar developmental stage. No vulva was formed.