598 



MR. F. E. BEDDARD ON THE 



[Dec. 6, 



occupies the middle of the length of the hemisphere and runs from 

 above downwards ; on the left side of the brain this furrow gives 

 oflf a faint branch which seems to be the Sylvian fissure — otherwise 

 hardly marked. 



On the inferior surface of the brain the rhinal fissure is seen to be 



Fig. 1. 



Brain of Capromys pilorides. 

 A, from above ; B, from the side. 



perfectly continuous and quite well marked from end to end. As 

 already mentioned, I found the greatest difficulty in discovering any 

 traces of the Sylvian fissure excepting in the lateral region of the 

 hemispheres, where it is present. 



Myopotamus coypu. — Total length 39 mm., breadth 28 mm., 

 height 14 mm. 



The cerebral hemispheres are nearly but not quite smooth ; there 

 being indications of furrows which are more strongly marked in 

 other genera. The extreme length of each hemisphere is 28 mm. 

 They diverge posteriorly so as to display a portion of the corpora 

 quadrigemina — both nates and testes ; the latter are, however, 

 partly concealed by a projection of the cerebellum. Anteriorly the 

 two hemispheres become very narrow and diverge in a marked wav 

 from each other ; passing back, the hemispheres rapidly increase in 



