172 PHYSIOLOGICAL SERIES. 



D. 206. The brain of a Bandicoot (Perameles sp.). 



The prominent floccular lobes (compare fig. 52) have been 

 removed from this specimen. 0. C. 1323 ci. 



Family DIDELPHYID^E. 

 D. 207. The brain of a Virginian Opossum (Didelphys 



This closely resembles the brain of Perameles and the 

 Uasyuridce. Note the well-defined rhinal fissure which 

 docs not extend the whole length of the hemisphere, so that 

 posteriorly the pyritbrm lobe and the neopallium become 

 freely continuous. 



Note the shallow orbital (presylvian) sulcus, especially 

 on the right hemisphere. 



The hemispheres have been separated in order to expose 

 the dorsal (hippocauipal) commissure placed in front of the 

 third ventricle. 



The cerebellum is simple like that of Perameles. 



O.C. 1323 u. 



Herrick, Journ. Comp. Neurol. vol. ii. 1892, p. 1. 



D. 208. The brain of an Opossum (Didelphys) , with the arachnoid 

 and pia mater in situ. 



This shows the true proportions of the olfactory bnlbeand 

 al-ohow much of the corpora quadrigemina is uncovered 

 by the cerebellum and cerebral hemispheres. 



O.C. 1323 B a. 

 Owen, Todd's Cyclopaedia, 1847, vol. iii. p. 292. 



Suborder DIPROTODONTIA. 

 Family MACUOPODID /:. 



D. 209. A series of five coronal sections of the cerebral hemi- 

 spheres of a Bennett's Wallaby (Macropus rujicollis). 



These specimens serve to demonstrate a peculiar bundle 

 of fibres (seen in tho second section), the presence of which 

 is peculiarly distinctive of the Diprotodont Marsupials. 



Tho uppermost section passes in front of the eerchral 

 commissures and shows the relations of the precommissural 



