Suppl. Fig. 4. from A feather star is born: embryonic development and nervous system organization in the crinoid Antedon mediterranea

Development of serotonergic neurons at the pre-hatching stage. Confocal z-projections showing serotonin immunoreactivity (green) and DAPI staining (grey) at the pre-hatching stage. A strong non-specific signal is detectable in the chorion membrane that surrounds the embryo before hatching (A). This signal was removed during image processing to reveal serotonergic cells in the developing apical organ (B, longitudinal section; C, sagittal section). Scale bar: 50µm.