Answer: ectoblasts

AnswerCrossword Clue
ectoblaststhe primordial outer layer of a young embryo before the segregation of the germ layers, capable of becoming the ectoderm and containing cells capable of becoming the mesoderm and endoderm
ectoblastsECTOBLAST, the outer layer of the blastoderm also EPIBLAST
ectoblaststhe ectoderm