EXPLANATION OF THE PLATES. 



PLATE XXXIV. 



DEVELOPMENT OF BONE. 



Fig. 1. Longitudinal section of the epiphysis and a portion 

 of the shaft of a foetal femur at the ninth month, 

 magnified 100 diameters, and showing the colum- 

 nar arrangement of the cartilage cells, together 

 with the increased size of the lower cells, and the 

 invading spiculae of the newly formed bone. 



Fig. 2. Transverse section of primary cancelli, magnified 

 350 diameters, showing the included nuclei of car- 

 tilage cells contained in the medullary cells or 

 spaces. 



Fig. 3. Transverse section of primary cancelli, magnified to 

 the same extent as the last figure, in a more ad- 

 vanced stage of their formation, many of the first 

 formed cancelli or septa having been absorbed as 

 well as the cell wall of the cartilage corpuscles 

 themselves. 



Fig. 4. Longitudinal section of the epiphysis and a portion 

 of the shaft of a foetal femur at the ninth month, 

 magnified 350 diameters. 



