44 



ANATOMY 



TABLE 14 



Summary of first appearances of ossification centers and of later bone changes in 



the albino rat (Wistar Institute Material— R. M. Strong, MS. 'S3). 



Sk^ill: 



Mandible. 

 Maxillae. . 

 Frontals. . 



Premaxillae 



Parietals 



Squamosals 



Basioccipital 



Vomer 



Palatines 



Pterygoid process of Basisphenoid. 

 Exoccipital 



Lacrimals. 



Nasals 



Jugals .... 



Interparietal. 



Tympanic 



Basisphenoid. 



Alisphenoidal process of Basi- 

 sphenoid 



Presphenoid 



Supraoccipital-paired centers. 



Alisphenoidal process united with 

 Basisphenoid junction still dis- 

 tinct at 



Orbitosphenoidal processes of Pre- 

 sphenoid 



In contact with Presphenoid 



Vertebrae: 



Arches 



First cervical to 2nd thoracic. 



Extended to 1st sacral 



In all arches 



AGE PERIOD 



Prenatal 



Days 



17 

 17 

 17 



17 

 17 

 17 

 17 

 17 

 17 

 17 

 17 



18 

 18 

 18 



18 

 18 

 18 



19 



19 

 19 



17 

 18 



Hours 



10 

 10 

 10 



8 

 10 



Birth 



Postnatal 



Days 



Hours 



22 



22 



Days 



19 



19 



Hours 



