G22 



PROF. R. A. DART ON THE 



Medially from this region can be seen an elevation of the lobus 

 meilius of tiie cerebellum, which is the most posterior structure 

 from the lateral aspect. It probably corresponds to the region 

 which gives rise to the cei'ebellar tonsil of human anatomy. 



Text- fig. 2 presents all those features emphasized by Elliot 

 Smith (1903) in his specimen {Zexiglodoiv elliotsmithii of this 

 paper). This natural cast reproduces very faithfully the convo- 

 lufcional pattern of the cerebellum and the position of the various 

 maniugoal vessels, particularly the sagittal sinus. This latter 



Text-figure 3. 



tO/Factory peduncle. 



^ Opt/c nen^e. 



%~~^^^0p/?t/?3//7?/c. d/V/si'on 

 oF trigeminus. 



/l^3x/7/ar/ d/V/s/'on 

 of tr/^ern//7us. 



fntertubercu/ar sulcus. 

 Tubercu/um o/factor/um. 



Gasserian ganglion. 



Tuber cincereum. 



Mandibular 

 division of 

 trigeminus. 



■ — Acoustic 

 nerve 



Medulla oblongata. 



•Ventral view of natural eiidocranial cast of Zeuglodon sensUious, sp. nov. M. 12123. 

 About i nat. siy.e. 



structure was described by Elliot. Smith (1903) as the "dorsal 

 rostrum." The knob-like elevations along its course are appar 

 renfcly veins entering it from the diploe of the skull. They bear 

 an extraordinary resemblance to human Pacchionian bodies. 

 Posterior to the prominence of the sagittal sinus and separating 

 it from the cerebellum is again seen the deep '' tentorial median 

 depression " already referred to, from which the tentorial sulcus 

 runs laterally on each side separating cerebrum and cerebellum. 

 .¥rom this aspect, too, the cerebellum is seen in complete detail — 



