Movie 1

Shows cleavage from a dorsal view of four embryos still in their jelly coats, from 4 cell through gastrula stages. Epiboly is evident beginning at around 30 hours elapsed time (frame 180). Embryos increase in diameter throughout cleavage and gastrulation. Mesendoderm migration during gastrulation is faintly visible through the blastocoel roof during gastrulation, starting about 50 hours (frame 300), and appears less coherent than that of Xenopus. 10 minutes elapsed time per frame. Playback at 15 frames per second (fps). Scale bar is 1 mm.