part of ends during starts during heart primordium cardiac progenitor cell xenopus_anatomy eriksegerdell XAO:0003268 CPC 2009-12-01T04:42:20Z Type of presumptive precardiac cell that lie as paired primordia 30 to 45 degrees on either side of the dorsal midline of the embryo. As gastrulation proceeds, these migrate laterally, eventually fusing at the anterior ventral midline, where they differentiate into cardiac tissue. They give rise to the linear heart tube of the fused heart primordium and derive from the cardiac crescent. progenitor cell NF stage 14 NF stage 19