ABSTRACT
In 1979 Donkelaar et al., 21 described the developmental stages of the Chinese hamster embryo from the first appearance of the somites to the end of the embryonic period as indicated by closure of the secondary palate. The period covered corresponds to Carnegie stages 9 to 23, but they divided this period of hamster development into stages 9 to 19. Pickworth et al. 22 described the first 5 to 6 days of development, i.e., from fertilization to beginning implantation. No information is available for the period between early implantation and the first appearance of somites.
