I04 



COMPARATIVE ANATOMY 



Osteogenic 

 tissue. 



Hyaline carti- 

 lage (cells in 

 groups). 



Hyaline car- 

 tilage (cells 

 enlarged) 



Osteoblasts. 



Endochondral bone. 



Fig. 77. — Development of cartilage bone (primary bone). Part of a longitudinal 

 section of a phalanx of the first finger of a human embryo of the fourth month. Ossifica- 

 tion within the cartilage produces endochondral bone; the perichondrium deposits bone 

 superficially to the cartilage, perichondral bone, and thereby becomes the periosteum. 

 X220. (From Bremer, Text-book of Histology.) 



