http://www.med.unc.edu/embryo_images/unit-welcome/welcome_htms/contents.htm

Embryo Images Normal and Abnormal Mammalian Development is a tutorial that uses scanning electron micrographs (SEMs) as the primary resource to teach mammalian embryology. The 3-D like quality of the micrographs coupled with selected line drawings and minimal text allow relatively easy understanding of the complex morphological changes that occur in utero. Because early human embryos are not readily available and because embryogenesis is very similar across mammalian species, the majority of micrographs that are utilized in this tutorial are of mouse embryos. The remainder are human.