Sudan Black (SB)–stained granulocytes in mindbomb and spadetail mutants. (A) Lateral and dorsal views of a 3 dpf mindbomb mutant. Note the accumulation of SB⁺ cells dorsally in the head. (B) Lateral views of 56-hpf and 78-hpf spadetail mutants. Note the increase in SB⁺ cells all over the body between the 2 stages, even though these mutants have no circulation in the trunk and tail (but normal circulation in the head, data not shown). At both stages, all SB⁺ cells in the tail and trunk are superficial (mostly subepidermal); none is in the CHT. (C,D) Histograms showing the number of SB⁺ granulocytes sorted by their localization throughout the embryo, in mindbomb at 48 and 72 hpf (C) and spadetail at 56 and 78 hpf (D) mutants. In both mutants, the granulocyte population increases 2-fold between the 2 stages examined. Cell numbers for the wild-type siblings are not shown because they are irrelevant to the point examined here.