XXX.] THE BRAIN. 311 



a. The anterior pyramids, two rounded cords 

 one on either side of the median line. 



b. The pons Varolii. At its lower edge are 

 transverse fibres forming a narrow band, the 

 trapezium, which dips down underneath 

 (dorsally of) the anterior pyramids; anteriorly 

 to this are transverse fibres forming a broad 

 band which runs over (ventrally of) the ante- 

 rior pyramids; the band has a median shallow 

 depression. In man the fibres of the trape- 

 zium are not seen on the surface of the pons. 

 Note on each side the continuation of the 

 transverse fibres of the pons into the middle 

 peduncle of the cerebellum. 



c. The inferior olivary bodies, two slight 

 oval elevations one on each side, laterally of 

 the anterior pyramid and just below the 

 trapezium. These will be seen more dis- 

 tinctly when the pia mater has been torn 

 away (cp. 10). 



d. The crura cerebri or peduncles of the 

 cerebrum, two broad roundish bands which 

 appear at the anterior edge of the pons, and 

 run forwards diverging from one another. 



e. The posterior perforated space between 

 the diverging fibres of the crura cerebri. 



/. The round projecting corpus albicans or 

 mammillare in front of the posterior perfo- 

 rated space. In the dog there is a shallow 

 median groove dividing it in two. 



