After gastrulation has occurred, the inner layer of cells is called what? 08:47 Animal Reproduction and Development After gastrulation has occurred, the inner layer of cells is called what? A - The mesoderm B - The ICM C - The endoderm D - The epiblast E - The ectoderm Answer: C - The endoderm Learn More : Share this Share on FacebookTweet on TwitterPlus on Google+