Figure 12-4. Diagrams showing implantation (x 45). A. Longitudinal section through horn of uterus about 5 days after mating. An ovum has recently become implanted in one of the uterine crypts. B. Longitudinal section through implantation site about 7 days after mating ( After Burckhard, 1901.)

Burckhard, G. 1901. Die implantation des Eies der Maus in die Uterusschleimhaout und die Umbildung derdelben zur Decidua. Arch. Mikroskop. Anat. 57: 528-569.