BIOLOGY OF THE LABORATORY MOUSE 



Very shortly after entering the uterus the eggs become spaced more or 

 less evenly throughout its length, and each egg finds its way into a uterine 



Mesometrium 



Blood vessel 



Uterine lumen 



" ^ ''^'' Circular muscle 



Longitudinal muscles 



Ovum 



Uterine 

 lumen 



Embryo 



Decidua 



Uterine gland 



Fig 4 -Diagrams showing implantation (X45)- 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) 



crypt on the ventral or antimesometrial side of the lumen, thereby coming 

 into close contact with the uterine epithehum (Fig. 3) • The presence of the 



