202 
TKUTIAliY VEliTEBKATA OF THE FAYtTM. 
(IVoiitiil) portion {f.l.) and a lateral (temporal) prominence {t.l.) by a ■\vell-marked 
depression, Avliicli seems to be liomologons with the “ pseudosylvian ” * depression {'p.) 
in the brains of recent Sirenians and Proboscidea. The cerebellum {ch.) is small, but 
its limits are not well shown in the cast. The base of the brain also is not well 
preserved, only the roots of one pair of nerves, probably the fifth, being shown. 
Text-fig. 65. 
Ca.‘;t of the cranial cavity of Eosiren Uhjjca : A, from above ; B, from right side. 
ch., cerebellum ; /./., frontal lobes ; ol., olfactory lobes ; 2>; pseudosylvian depression ; t.J., temporal lobes. 
f nat. size. 
In Entherunn the general form of the brain is not unlike that figured, but the 
pseudosylvian depression is very slightly marked, so that the separation of the hemi- 
spheres into anterior and lateral lobes is obscure. 'J’he chief interest of the brain of 
Eosiren lies in its remarkable similarity with that of Ma'rithcrinm [vf. text-fig. 41, 
]). 100). In both animals the hemispheres are divided in a quite similar way by the 
pseudosylvian deju'ession, and the cerebellum is relatively small. In Moerithermm^ as 
* Elliot Smitb, ‘Catalogue of the Physiological yeries. Museum, Coll. Surgeons,’ vol. ii. cd. 2 (lt)02) 
p. 311. 
