title: A presomite human embryo of Horizon VII.
abstract: A presomite embryo of Horizon VII aged approximately 18 days is described and illustrated. It is compared with some other embryos of a similar age, and a considerable variation of histological characteristics within the same Horizon is noted.
mesh_terms: D002823:Chorion / Q000166:cytology; D002824:Chorionic Villi / Q000166:cytology; D004475:Ectoderm / Q000166:cytology; D004622:Embryo, Mammalian / Q000166:cytology*; D006801:Humans; D008648:Mesoderm / Q000166:cytology