Sixteen cell stage Zebrafish embryo. The first frame shows cells at metaphase. The sequence covers the next four cell cycles. In each prophase, there is a rapid onset of yolk platelet motility. Yolk material is fragmented off the yolk cell and drawn into the outermost blastomeres through cytoplasmic bridges. This video made available by Mark Cooper thru Zebrafish - The Living Laboratory. The videos in this group can also be found in the Developmental Landmarks page of the Fishscope web site.