THE CRANIAL SKELETON. 



107 



here that it is only found very elongated and anchylosed to 

 the skull in man, though an anchylosed but less elongated 

 one is sometimes found in a species of Baboon. 



103. Under Surface of the Skull of the Lemur Microcebns minor, showing 

 the inflated auditory bullae (on each side in front of the foramen magnumj, and 

 alo the defects of ossification in the bony palate. 



The tympano-hyal will also be noticed with the hyoidean 

 structures. Only in Mammals, but in them constantly, does 

 it form a process of the skull. Its common form, as in the 

 Dog, is that of a small cylindrical truncated process, between 

 the tympanic bulla and the paroccipital process. In man it 

 is obscured by anchylosis with the styloid process, of which it 

 forms the root. 



23. The SPHENOID, like the temporal bone of man, is a 

 highly complex one, as is made evident by what we find in 

 other animals. 



The body of the sphenoid is a less constant structure as a 

 distinct bone than might be supposed. On the other hand, that 

 close union between it and the basi-occipital, which in adult 

 man is constant, is rarely found elsewhere. Even the body of 

 the sphenoid itself, in Mammals, is generally formed of two 



