NEKVOUS SYSTEM. VEETEBRATA. 183 



and the smaller Macropods. The arrangement of the three 

 sulci which diverge from the region of the angle of the 

 rhinal fissure is identical with that of the Giant Kangaroo. 

 But there is a sulcus, the u paramedian/' springing from the 

 postero-superior part of the great arc formed by the supra- 

 sylvian and sulcus B, which is not represented in the 

 Kangaroo's brain. It proceeds obliquely backward to the 

 postero-mesial corner of the upper surface. This sulcus 

 is seen in its typical form on the left hemisphere only : 

 on the right side two small sulci take its place. The 

 interest attaching to the paramedian sulcus is that it is a 

 very characteristic feature o the smaller Macropodidse. 



O. C. 1323 A b. 



Ziehen, Jena. Denkschr., Bd. vi. 1897, p. 71. 



[In Ziehen' s specimen the sulcus A, his i/r, is much more 

 imperfect than in this specimen.] 



D. 219. The brain of a Derbian Wallaby (Macropus derbianus). 



This is not unlike the brain of Bennett's Wallaby. 



The cerebral hemispheres have been separated from 

 above in order to expose the dorsal or hippocampal com- 

 missure, which may be seen as a narrow transverse band in 

 front of the third ventricle. 0. C. 1323 A h. 



Ziehen, Jena. Denkschr., Bd. vi. 1897, p. 71. 



D. 220. The brain o Rat- Kangaroo (Bettongia gaimardi) ( ? ). 



The pallium is almost devoid of sulci, and in shape not 

 unlike that of the Phalangers. There is, however, on the 

 caudo-mesial angle of the dorsal surface the characteristic 

 paramedian sulcus of the Macropodidae. This sulcus prob- 

 ably represents the " lateral sulcus " of the Rodents, 

 Ungulates, and Carnivores. 0. C. 1323 A q. 



Gervais, Nouv. Arch. Mus., t. v. 1869, p. 240. 



D. 221. The brain of a Tree-Kangaroo (Dendrolagus inustus) ( ? ), 

 in which the left hemisphere has been separated from the 

 rest of the brain. 



The olfactory bulbs have been removed. In shape the 

 cerebral hemispheres and the cerebellum conform to the 

 Macropod type. But the hemisphere is remarkable for 



