638 



cartilagineons preformed, viz. the os iiitertemporale from Ranke ^). 

 Perhaps both ways of enlargement of the temporal in forward 

 direction occnr; only ontogenetical and comparative anatomical 

 investigations conld make out this question. 



Ossa epipterica. 



I have brought the ossa epipterica to the following types. 



I. Os epiptericum bordering to four bones (frontal, parietal, 

 temporal, alisphenoid) : os epiptericum typicum. 



II. Os epiptericum, bordering to three bones. 



a: frontal, parietal, alisphenoid: os epipt. anterius. 

 /> : parietal, temporal, alisphenoid : os epipt. posterius 

 c: frontal, parietal, temporal: os epipt. superiiis 

 d : frontal, temporal, alisphenoid : os epipt. inferius. 



III. Os epiptericum, bordering to two bones; i.e. presenting itself 

 as a siitural bone. 



IV. Several ossa epipterica. 



Thirty times I found an os epiptericum typicum 

 in 4 skulls on both sides 

 ,, 15 ,, ,, the right side 

 ,, 11 ,, ,, the left side. 



If an OS epiptericum typicum is present on both sides of the 

 skull, the two bones are symmetrical in situation and extension. 



If an OS epiptericum is only present at one side of the skull we 

 find, when examining the other side of the same skull the follow- 

 ing cases: 



I. Os epiptericum typicum at the right side 



a frontal process at the left side in 4 skulls. 



a spheno-parietal suture ,, ,, ,, ,. ,, 5 ,, 



a frontal process and an os epiptericum ,, ,, ,, ,, ,, 3 ,, 



Several ossa epipterica ,, ,, ,, ,, ,,2 



II. Os epiptericum at the left side 



a frontal process at the right side in 2 skulls, 



a spheno-parietal suture ,, ,, ,, ,, ,, 6 ,, 

 Several ossa epipterica ,, ,, ,, ,, „ 1 ,, 

 This survey proves that the side of the skull, opposite to an os 



1) Ranke. -1. Ueber den Slirnforlsalz dei' Schlafenschiii)pe l)ei den Primaten, 

 öilzungsber. bayi'. Akad. d. Wissenscli 18Ü8. 



