Fig. 5. Ray morphology in P. pacificus wild-type (A) and Ppa-mab-5(tu34) mutant animals (B). The spacing and position of wild-type rays (arrows) is different from the one in C. elegans. Two rays open laterally (arrowheads). R7-R9 are clustered at the tip of the animal. R1-R6 are absent in Ppa-mab-5. R7-R9 are present (arrow in B) but not all rays are visible in this plane of focus. Anterior is towards the left and dorsal is upwards.