NERVOUS SYSTEM. - VERTEBRATA. 331 



D.445. The brain of an Elk (Alces machlis), 



This is a typical Deer's brain. 0. C. 1328 E g. 



Presented by the Zoological Society. 



D. 446. The brain of a Roe Deer (Capreolus caprea), ( ? ). 



In spite of its much greater size., this brain is only very 

 slightly more complicated than that of the Chinese Water- 

 Deer, which it resembles. 



The posterior descending limb of the suprasylvian sulcus 

 has completely aborted and a horizontal sulcus has 

 developed below the posterior horizontal ramus of the 

 suprasylvian, which may be regarded as a compensatory 

 sulcus. 



The orbital sulcus is still placed very far forward and a 

 paraorbital sulcus is formed by the cephalic extension 

 o the anterior ectosylvian sulcus, which is prolonged 

 obliquely upward and forward as a deep incision in the 

 upper opercular lip of the anterior rhinal fissure. 



The splenial complex is placed much higher than in 

 Hydropotes, so that it comes to lie on the dorsal rather 

 than the mesial surface. This is just the reverse of what 

 we should expect after a study of the brain of other Deer, 

 for, as a rule, the larger the brain the more mesial and the 

 nearer the corpus callosum the position of the conjoint 

 calcarine and intercalary sulci is. 



There is a most pronounced crucial-like lateral bending 



of the anterior extremity of this sulcus. 0. C. 1328 E e. 



Presented by Sir Victor Brooke, Bart. 



D. 447. The brain of a Chinese Water-Deer {Hydropotes inermis). 



" In its cerebral organization Hydropotes approaches 

 the genus Capreolus more nearly than any other Cervine 

 form known to me " (Forbes). 



In the greatly simplified arrangement of sulci in this 

 brain, the type common to all the Deer is well exemplified. 



There is a simple vertical " Sylvian fissure " (fig. 192, 

 S.), ascending from the rhinal fissure ; a long, simple, 

 orbital (presylvian) sulcus, also springing from the latter 

 far forward on the anterior pole ; a simple semicircular 

 suprasylvian sulcus with a short posterior descending limb 

 and a longer posterior horizontal ramus, its anterior 



