Chap. IX.] 



AND OF BIRDS. 



127 



of higher Yertehrates (fig. 58, h). Between the optic 

 lobes and the next great division of the brain, the 

 cerebral lobes, we find the so-called ' pineal body ' (fig. 

 61, j), projecting upwards, and in a more developed form 

 than that which is met with in Fishes. The nature and 

 uses of this body are wholly unknown. It is chiefly 

 notorious from the fact that Descartes pointed to the 

 corresponding structure in the human brain as the " seat 

 of the Soul." 



The Cerebral Lobes in the Lizard (fig. 59) and its allies, 

 as well as in Amphibia, are, in comparison with other 

 parts of the brain, much larger than in 

 Fishes. This is due only in part to an 

 absolute increase in their development, as 

 there seems to be some diminution in the 

 size of the olfactory and optic lobes and the 

 cerebellum. In Serpents, Crocodiles, Tur- 

 tles (fig. 61), and their allies, however, we 

 meet with a decided absolute increase in the 

 size of the cerebral lobes. In Crocodiles, 

 for instance, they are much larger and 

 broader than other parts of the brain, 

 though their surface is still quite smooth. 

 Each lobe contains a cavity or ' ventricle ' 

 in its interior, as in some of the higher 

 Fishes. But in Reptiles the i^entricle is 

 larger, and, projecting from its anterior 

 and inner surface there is a rounded emi- 

 nence, supposed by some anatomists to represent a body of 

 considerable importance — which is known amongst higher 

 vertebrates as the ' Corpus Striatum ' or striate body. 



Each Cerebral Lobe is connected with its corresponding 

 optic lobe and with the same half of the medulla oblongata, 

 by means of a thick and composite prolongation called the 



Fig. 59.— Brain of 

 Lizard (Lacerta viri- 

 dis). a, Cerebral 

 hemispheres ; b, op- 

 tic lobes ; c, cerebel- 

 lum ; d, spinal cord ; 

 e, fourth ventricle ; 

 /, ijineal body ; g, 

 olfactory ganglia. 

 (Owen.) 



