800 



Mti.. Pi E. iBEDDAUD ON THE 



[June 20^ 



Behind the optic cliiasma is a large somewhat heart-shaped 

 elevation (c, d). It is divided anteriorly by a median furrow which 

 is well-marked and deep ; behind it shows indications o£ division 

 into two. This elevation appears to me to be the tuber cinereum 

 and the corpora albicantia partly fused, but whose independence 

 is still to be recognized on a careful examination. 



Fig. 2. 



Brain of Hydrochxrus, ventral view. Nat. size. 



5, pallium ; h, olfactory nerve ; a, origin of same ; c, tuber cinereum ; 

 d, corpora albicantia ; p, pituitary body. 



Other features to be noted on the ventral surface of the brain 

 will be seen by an inspection of the accompanying drawing. 



Fissures of the ffemispheres. 



I shall take as an assumed normal the best preserved of my 

 three brains, indicating the divergences in arrangement which the 

 others show. 



The most salient fissure is that lettered a (fig. 1). It runs 

 almost from end to end of the brain ; at about the middle of its 

 course it is bulged out on either side, and on the left side it is just 

 interrupted by a bridging convolution, and is thus divided into two 



