Skull , Brain, cbc. o/'Diadcmodon. 



219 



notched at the back so as to allow of a connection between 

 the two organs. 



Above the processus anterior inferior prootici is a notch 

 for the V. nerve, above and in front of which the prootic is 



Fig. 1. 



Posterior part of the brain-cavity of Diademodon, slightly diagrammatized 

 from the type-skull of D. entomophonus. X 1|. 



Duc.Endo.— opening of the canal for the ductus endolymphaticus into 

 the brain-cavity. Foss.sub.arc.=- fossa subarcuatn. />>■/. = vestibular 

 cavity, p' and v" , foramina for veins. V, Y II, IX, X, XI, XII, 

 foramina for exit of the corresponding cranial nerves, 



carried forward as a long process covered externally by the 

 alisphcnoid. In the suture between this part of the prootic 

 and the parietal is a venous foramen opening outward into 

 the sinus-canal. 



Bones of the Brain-case. 



The basioccipital and basisphenoid are not separated by 

 suture ; they are in the cerebellar region very shallow bones, 

 deepening in front until, at the pituitary fossa, the basi- 

 sphenoid is transformed into a deep narrow plate, which 

 carries the laterally directed basipterygoid processes, 



This specimen shows quite clearly that no foramen opens 



15* 



