Common origin of primD and primII. A, D0 splits to form primD and primII around 42 hpf. Arrows indicate the directions of migration. B, Uncaging fluorescein in D0 at 36 hpf results in the presence of labeled cells in D1, the first neuromast deposited by primD, in primD-, primII-, and primII-derived interneuromast cells (INC II). Anterior is to the left, and dorsal is up. Scale bars, 50 μm.