PHYSIOLOGY: PRACTICUM VIII: PLATE XX. 



BASE OF SHEEP'S BRAIN AFTER THE REMOVAL OF THE HYPOPHYSIS 

 AND PARTS OF THE CEREBRUM AND CEREBELLUM ; enlarged. 



olfactory bulb 



INSULA 



olfactory fissure 



PREGENICULUM ' 

 POSTGENICULUM -- 

 CRUS 



CEREBELLUM 



olfactory crus 



1 



2 



precribrum 



optic nerve 



chiasma 



.OPTIC TRACT 



lura 



TUBER 



albicaus 



postcribrum 



oculo-motor nerve 



-- trapezium 



.. oliva 

 - - pyramid 



_ my el 



The cephalic and caudal regions are nearly the same as in PI. XIX, but the following 

 differences should be noted : a. The absence of the frontal parts of the cerebrum be- 

 tween and laterad of the OLFACTORY BULBS, b. The indication of the MESAL (i) 

 and LATERAL, (2) ROOTS of the bulb. c. Between the two the irregular triangular area, 

 PRECRIBRUM ("anterior perforated space") presenting orifices for the transmission of 

 vessels, d. The removal of the HYPOPHYSIS ; this exposes a slight elevation, TUBER, 

 and an orifice, lura, leading into the diacoele. e. The CRURA and OPTIC TRACTS 

 are more fully seen. f. The PONS presents more distinctly the mesal emargination of 

 its caudal margin. 



i, Mesal root of olfactory bulb. 2, lateral root. 3, cut surface of olfactory tract and 

 pallium. 4, depression caused by the extraction of the right oculo-motor nerve. 5, Cau- 

 dal emargination of the puns. 6, Ventral mesal sulcus of the oblongata. The unnamed 

 shaded line across the crus just cephalad of the oculo-motor nerve was intended to repre- 

 sent the cimbia. 



