On the cover: Image stack projection of transverse confocal sections of 74-hpf wild-type zebrafish larvae showing the aortic arch vessel in green and BrdUrd labeling in white. Vessels are visualized for Tg(flk1:EGFP)^s843 expression, and BrdUrd incorporation was done from 59 to 74 hpf. See related articles, pages 1253 and 1260.