Fig. 5. Direct visualization of Rohon-Beard cells in mao mutant and sibling embryos. RB cells in mao sibling (A) and mutant (B) 72 hpf embryos were directly visualized with Hoffman optics. RB cells (arrows) are easily recognized on the basis of their dorsal position and relatively large size within the spinal cord (Grunwald et al., 1988). More RB cells are present in mao mutants than sibling embryos. Scale bar: 20 µm.