NETJKOLOaY OF THE SATJROPSIDA. 



303 



Init in Aves (Fig. 90 B, D) tliey are thrown down to the' 

 sides of the base o£ the brain, and are connected over the 

 aquceductus Sylvii by a broad commissural band. 



Each prosencephalic lobe contains a lateral ventricle 



Fig. 91. 



Oijf 



Fi". 91. — The brains of a Lizard (Fsammosaurus hengalensis) and of a 

 bu-d {3Ieleagris gallopavo), in longitudinal and vertical section. The 

 upper figure represents the lizard's brain ; the lower (taken, like 

 fig. 90, B, D, from Carus' "Erlaiiterungs-Tafeln") that of the bird. 

 The letters as in the preceding figure, except L. t., lamina termi- 

 nalis, or anterior wall of the third ventricle ; /. 31., foramen of 

 Munro ; a., anterior commissure ; 27i. E., thalaniencephalon ; 

 «., soft commissure; p., posterior commissure; iv., indicates the 

 exact point of exit of the fourth pair from that part of the brain 

 which answers to the valve of Vieussens. 



