BRAIN OF THE ZBUGLODONTIDiE. 



633; 



The lobiis medius, or area crescens, is not only veiy asym- 

 metrical but is poorly developed, and the paraflocculi form by far the 

 greatest part of the cerebellar mass. The posterior view affords 

 perhaps the completest picture of this atrophic brain, for here Ave 

 recognise the general flattening out or " cake-like " appenrance of 



Text-fiffure 16. 



Offactory peduncle. 



Ssgittat sinus, 

 'r/gemtnus 



M'M/e cerebmr/ 

 t^essel 



_^V, Cerebri/ hem/sp^ipre 



Gasserran gang/io/7 

 & mtcfd/e 

 cerebri/ ves^efs 



Psrjfyoccijlus 



Jugular lessh. 



'US med/us cerebetli. 

 'A^edu//a oblongata. 



Dorsal view of eudocranial cast of Zeuglodon osiris Dames. M. 10228. 

 About ^ nat. size. 



this brain (which came from a perfect skull) and also the 

 extremely long but narrow cross-section of the medulla oblongata. 

 This view of the medulla oblongata coupled with the latei-al view 



Text-figure 17. 



Lobus medius cerebelli. 



Posterior view of endocraiiial cast of Zeuglodon osiris Dames. SI. 10228. 

 About ^ nat. size. 



of this region corroborate the inference we have ah'eady drawn 

 tliat in Zeuglodon osi7Hs we have the degenerate offspring of a, 

 specialised race. 



The degree of this degeneration is perhaps most graphically 

 shown if we compare the cubic capacity of this brain (480 c.c.) 



