226 



Mr. D. M. S. Watson on the 



The brain-case in the region of the optic lobes and 

 cerebrum has not been cleared, but as its lower surface is 

 widely open and the walls the thin plates of the epipterygoid, 

 a cast would not be likely to yield any information of value. 

 The maximum possible breadth of the cerebrum is known, 

 and is very much less than the width across the cerebellum. 



Fig. 4. 



Skull of Diademodon entomophonus, restored. Dorsal aspect. X { 



Stippled area=cavifcy for the brain; lined ai*ea= vestibule and its 

 processes ; semicircular canals black. 



The ironstone cast It. 3767 shows the front of the brain 

 quite well ; the thin plates of epi pterygoids which enclose it 

 very nearly meet in the ventral line, and the upper surface 



