46 



ANATOMY 



TABLE 14 Concluded 



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, slight differences in time of first ossification for 

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

 showed only trivial variations in the time of first ossification. 



