Some Considerations respecting the Parietal Bone. 331 



sphenoids, and lachrymals being intermediaries in certain directions. 

 It will be seen that even in the same genns considerable variations 

 may occur. The relative proportions may be maintained by alteration 

 of the forces whatever these may be, so that a growth forward of the 

 parietals in the middle line may bring the interparietal fissure up to 



Fig 26. 

 Pteropus Edwardsi. 



the length of the interfrontal fissure, or shortening may take place 

 in the frontal so that the same proportion may be brought about. 

 The anterior inferior angles may be studied as they advance or recede 

 relatively to the neighbouring bones. 



'J'he following table II gives a collected list of some rodents and 

 Unflates. 



