276 



ZOOLOGY 



SECT. 



plane. The corpora striata, or basal ganglia of the cerebral hemi- 

 spheres, are connected together, as in all Vertebrates, by an anterior 

 commissure (D, com, below, lower line), above which is another com- 



fiin 



A fed. cbl 



FIG. 946. Brain of Rana. A, from above ; B, from below ; C, from the side ; D, in longitudinal 

 vertical section. Cb, cerebellum ; Cer. H, cerebral hemispheres ; ch. plx 1 , anterior, and 

 ch. plx z , posterior choroid plexus (removed in A) ; com, commissures, the two in front the 

 anterior and hippocampal, the two above the superior or habenular arid the posterior ; Cr. C, 

 crura cerebri ; Di, diencephalon ; for. M, foramen of Monro ; i, iter, or aqueduct of Sylvius ; 

 inf, infundibulum ; Med. obi, medulla oblongata ; Olf. I, olfactory bulb ; opt. ch, optic 

 chiasma ; Opt. I, optic lobe ; opt. v, optic ventricle ; pin, stalk of pineal body ; pit, pituitary 

 body ; Sp. cd, spinal cord ; ;{ , third ventricle ; o 4 , fourth ventricle ; / X, cerebral nerves ; 

 ISp. 2Sp. spinal nerves. (From Parker's Practical Zoology. A C, after Gaupp ; D, from 

 Wiedersheim's Comparative Anatomy, after Osborn.) 



