SMITHSONIAN CONTRIBU TIONS TO KNOWLEDGE 



VOL. 35, NO. 3. PL. 1 



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liU. 1 



Rij;ht femur of a large bull frog (Rana catesbiana), 

 showing radiating bush-like canals 



Fig. 2 

 Right femur of a medium-sized bull frog (Rana 

 catesbiana), the radiating canals disappearing 



Fig. 3 

 tiight femur of a small bull frog (Rana catesbiana), 

 in which radiating canals are displaced by lamellae 



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Km. 4 



Uight femur of a bull frog showing tlic first t.>pc 



of structure 



Fig. 5 

 Fractured and repaired femur of a bull frog (Rana 

 catesbiana), showing new cancellous bone of repair 



AMPHIBIANS 



