180 PHYSIOLOGICAL SERIES. 



The cephalic portion of the fascia dentata and Un- 

 characteristically bilaminar dorsal commissure of the Macro- 

 podidee are well demonstrated. 0. 0. 1323 A i. 



D. 214. The right hemisphere of the same brain of the Giant 

 Kangaroo (Macropus gigariteus) as specimen D. 213, cut 

 transversely through the two cerebral commissures. 



Upon the mesial surface of the hinder [lower in bottle] 

 fragment the arrangement of fascia dentata and fornix 

 typical of the Marsupial in, and already described in the 

 Black-faced Kangaroo, may be seen. 



The features of a coronal section through the commissures 

 are seen, perhaps, to better advantage than in speci- 

 men D. 209. 0.0. 1323 A k. 



D. 215. A cast of the cranial cavity of a Giant Kangaroo 

 (Afacropus giganteus). [In duplicate.] 



This cast shows the true shape and proportions of the 

 largest brain of an existing Marsupial, and permits us to 

 compare the impression of the interior of the cranium with 

 actual brains of the same species. We are thus able to 

 appreciate to how great an extent we can rely upon casts 

 of the cranial cavity in the interpretation of the features of 

 the brain in such extinct forms as Tliylacoleo. 



The shape of the large projecting olfactory bulbs is shown 

 more accurately than in the other specimens. This peculiar 

 form of bulb occurs also in all the Lemuroidea and in 

 many Ungulates. Note also the pronounced ventral 

 extension of the postsylvian area of neopallium and the 

 very marked tapering of the anterior poles of the hemi- 

 spheres. The relation of the hemispheres to the cerebellum, 

 olfactory bulbs, and the pituitary body is very strikingly 

 demonstrated. 



It will be seen that from such a cast as this it is possible 

 to map out the pattern of the cerebral stilci with alm< 

 much certainty as in the actual brain. 



Thus we see the deep orbital and the shallower pron-.-m 

 sulci, just as'clearly as in specimen D. 211. Tin- two 

 pseudosylvian sulci diverging from the angle of the rhiiuil 

 r.ro also clearly exposed. The great V-shaped sulcus which 



