DEVELOPMENT OF BONE. 



71 



and either replaced by true or fibrous bone which has been formed by 

 osteoblasts, or swept away to form the medullary cavities. 



sp 



FIG. 79. PART OF THE GROWING EDGE OF THE DEVELOPING PARIETAL BONEjOP A 

 FOETAL CAT, 1J INCH LONG. (From a drawing by Mr. J. Lawrence.) 



sp, bony spicules, with some of the osteoblasts embedded in them, producing the lacunae ; of, 

 osteogenic fibres prolonging the spicules, with osteoblasts (ost) between them and applied 

 to them. 



