626 



PROF. R. A. DART ON THE 



total length and height of the bvain-mass were considernhly 

 Kniiiller in this species. 



The bulk of the endocranial cast (average of five separate 

 measurements by water dispUxcement) of Zeuglodon ellioisviithii 



Text-fisfure 6. 



Otfactory pe<func/e. 



Trigeminus. 



MiM/c cerebra/ 

 vessels 



Carebral he&iispliere. 



Pars flocculus. 



Lobus mecfius 

 cerebelli. 



Dorsal view of endocranial cast of Zeuglodon elliotsmithii. M. 12066. 

 About \ iiat. size. 



wns 300 c.c. Elliot Smith gives (1903) 410 c.c. ns the bulk of 

 this " natural cast (including that of a considerable qnantity of 

 matrix attached to the base of the brain and some smsill fiag- 

 ments of bone)," but states that the actual weight of the brain 



Text-fin;ure 7. 



LobuS niec/ius 



cerebelli'. 



Pjr.3f/occu/u3. /f ^ ^, 



%4 



Broken mc>r(^in of cast. 



Posterior view of endocranial cast of Zeuglodon elliotsmithii. M. 12060. 

 About i nat. size. 



wns probably "nearer 300 grammes," In this latter estimate I 

 am inclined to agree. But whereas the bulk of Zeuglcdon elliot- 

 S'tiiithii could not have been very much greater than 300 c.c, that 

 of the natural cast of Zeuglodon sensitivus (in which the medulla 



