NORMAL HISTOLOGY. 



Embryona! 



cartilage 





Cartilage-cells becoming 

 enlarged and grouped 



i< <f .-':. 



PK 



Zone of calcification ^tffi 



1 

 II 



Osteognetic layer of >jf^ f 

 periosteum " 'H 



':> 



Central spongy bone 



enclosing remains of 



cartilage 



FiO. 57. Longitudinal section of metatarsal bone of foetal sheep, showing endochondn.1 bone 



development. X 40. 



