THE SKULLS OF MAMMALIA. 



2(33 



temporal fossae, where they unite, in front, with the apices of the 

 tolerably large orbito-sphenoids, and behind, with the periotic 

 and supra-occipital. Below the inferior margin of the parietals 

 the squamosals appear largely in the lateral wall of the skull. 



The alisphenoids are very small, and are directed horizon- 

 tally outwards. The foramen for the exit of the third division 

 of the trigeminal is between the hinder margin of the bone and 

 the periotic. 



The latter bone has a considerable proportional size, and is 

 devoid of any cerebellar fossa. 



Fig. 103. 



JPet 



Fig. 103. 



no -2W 



-Longitudinally and vertically bisected cranium of a foetal Elephant (Elephas 



Indians). 



On the exterior of the skull the squamosal joins the ex-occi- 

 pital, so that no "pars mastoidea" appears upon the surface. 

 The post-glenoidal and post-auditory processes of the squamosal 

 are very large, and bend towards one another inferiorly, so as to 

 meet (in the adult skull) and form a spurious external auditory 

 meatus. 



But besides this, there is a true external auditory meatus 

 which is, as usual, an outgrowth from the tympanic. The latter 

 bone is very large and bullate. It is grooved anteriorly by the 

 carotid, and the short styloid process appears between it, the 

 squamosal, and the ex-occipital. 



The tympanic and the periotic are anchylosed together and 

 wedged into the space left between the ex-occipital, squamosal, 

 parietal, alisphenoid, and the basi-cranial axis. 



The very short nasal bones (absent in the specimen figured) 



