NERVOUS SYSTEM. VERTEBRATA. 333 



D. 448. The brain of a Chinese Water-Deer (Hydropotes 

 inermis), (c?). 



This specimen shows better than the last how closely the 

 brain conforms to the same type as that of the Musk-Deer. 

 The pseudosylvian sulcus is longer and more complete, for 

 the depressed area is now almost completely hidden by the 

 downgrowth of opercular folds, especially in front of the 

 sulcus. As a result the orbital sulcus now appears to 

 spring far forward from the rhinal fissure. 



The anterior part of the suprasylvian sulcus is prolonged 

 beyond the junction with the coronal sulcus, and a vertical 

 secondary sulcus (the diagonal of Krueg) has made its 

 appearance between the coronal and suprasylvian sulci. 

 The diagonal is not joined to the suprasylvian sulcus as it 

 is in the last specimen. 



There is a longer lateral sulcus than there is in the 

 Musk-Deer. The splenial sulcus is now wholly mesial, 

 probably because the brain is larger. It does not, how- 

 ever, extend so far forward. The genual sulcus is 

 longer and so also is the rostral, which appears to cross 

 the dorso-mesial margin of the hemisphere and join the 

 coronal sulcus. 0. 0. 1328 E k. 



Presented by the Zoological Society. 



D. 449. The brain of a Mexican Deer ( Odocoileus mexicanus] . 



This brain is a larger and correspondingly more com- 

 plicated copy of that of Capreolus. 



The true nature of the paraorbital sulcus is clearly seen. 



There is no posterior descending ramus of the supra- 

 sylvian sulcus, but the posterior horizontal branch is very 

 deep and extensive and its ventral compensatory sulcus is 

 also extremely well developed. 



Well-defined ecto- and entolateral sulci have made their 

 appearance. 0. C. 1328 Ea. 



D. 450. The brain of a Virginian Deer (Odocoileus virginianus) . 

 This brain agrees with the description of 0. mexicanus. 



0. C. 1328 E p. 

 Presented by the Zoological Society. 



