46 



ANATOMY 



TABLE U— Concluded 



Carpals all had some ossification 



Metacarpals: 



Third 



Second and fourth 



Fifth 



First 



Phalanges of hand: 



Terminal phalanx the first to show- 

 ossification 



All phalanges except 1st of 1st digit.. 

 All phalanges 



Tarsals: 



Astragalus 



Calcaneus 



All others 



Metatarsals: 



Third 



Second and fourth 



Fifth 



First 



Phalanges of foot: Terminal phalanx of 



all five digits 



All phalanges 



AGE PERIOD 



Prenatal 



Days Hours 



18 

 19 

 21 



18 

 19 

 21 



21 



10 

 10 



Birth 



Days Hours 



Postnatal 



Days Hours 



10 

 10 



22 



19 



2 



2 



14 



In table 14a Strong compares the fetal ages in the rat and 

 man at which the first ossification appears. In the rat the in- 

 terval between the first and last instance is 5 days and 18 hours, 

 while in man it is 56 days. The fraction of the gestation period 

 required by the rat is slightly greater than that required by man. 



Occasionally, shght differences in time of first ossification for 

 right and left sides were found. The individuals of a fitter 

 showed only trivial variations in the time of first ossification. 



