342 



AN INTRODUCTION TO ZOOLOGY 



That portion of the cerebrum lying within the limits of 

 the rhinal fissures may be regarded as the ventral surface of the 

 telencephalon, and calls for notice owing to the presence thereon of 



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FO 



XII 



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FIG. 1 1 8. Brain of sheep, ventral aspect, adapted from Burkholder. 



C.C., crus cerebri ; Ce., cerebellum ; C.M., corpus mammilare ; C.T., corpus trapezoideum ; 

 E.O., external olfactory root ; F.S., sagittal fissure ; H.L., hippocampal lobe ; M., medulla : 

 M.O., median olfactory root ; O.C., optic chiasma ; O.L., olfactory lobe ; Op.T., optic tract ; 

 O.T., olfactory tubercle ; P.L., pyriform lobe : P.P., posterior perforated spot ; P.V., pons Varolii ; 

 R.F., rhinal fissure ; S.C., spinal cord ; T.C., tuber cinereum ; V.P., ventral pyramid ; II.-XII., 

 roots of cranial nerves. 



certain important structures. Right at the front end, and pro- 

 jecting slightly beyond the hemispheres, are two obliquely directed 

 olfactory lobes, completely separated by the sagittal fissure which 



