NERVOUS SYSTEM. VERTEBRATA. 165 



rest of the cerebellum by a deep fissure. This is the 

 floccular lobe. In man the representative of this mass 

 becomes reduced to very insignificant proportions and forms 

 the flocculus. In this brain, however, the floccular lobe is 

 almost, if not quite, equal in size to the whole of the rest 

 of the so-called lateral lobe. Two shallow sagittal grooves 

 separate the upper surface of the cerebellum into three 

 projecting ridges, each of which is subdivided by a small 

 series of transverse furrows. In each of these grooves a 

 triangular area of medullary matter is exposed. The area 

 seen in this specimen between the floccular lobes corresponds 

 to that region of the human cerebellum which lies behind 

 and below the preclival fissure and in front of the uvula. 

 Part of the uvula in this specimen may be seen as a little 

 tongue-like process extending backward and forming an 

 operculum over the apex of the fourth ventricle. The 

 most significant feature of this organ to the human anatomist 

 is the extreme diminution of the lateral hemispheres; but 

 when the intimate association existing between the cere- 

 bellar hemisphere and the opposite cerebral hemisphere is 

 remembered, it is not surprising to find these parts of the 

 cerebellum so poorly developed in a brain in which the 

 pallium as a whole, and especially the neopallium, is so 

 diminutive. The anterior lobe, which is relatively so large 

 in the Monotremes, is completely hidden in this brain by 

 an overhanging hood formed by the region lying behind 

 the fissura prima (vel prseclivalis). 0. C. 1323 B b. 



B. Owen, Todd's Cyclopsedia, 1847, vol. iii. p. 291. 



D. 198. The brain of a Tasmanian Devil (Sarcophilus [Dasyurus] 

 ur sinus). 



This specimen shows the real proportions of the huge 

 olfactory bulbs. The hemispheres have been drawn apart 

 so that a much greater part of the corpora- quadrigemina 

 is exposed than when the parts are in their natural position. 

 [Compare the casts D. 199 and fig. 47.] 



This specimen is represented in Owen's ' Anatomy of 

 Vertebrates,' vol. iii. p. 104. 0. C. 1323 c/. 



