534 THE HIGHER ANTHROPOIDS 



tlu' M'litral gray matter and continues upward as a Hat strand showing but 

 littk- inclination to increase in size. Upon the first appearance of the nucleus 

 of Burdach, the nucleus of Goll shows cielinite and marked expansion in its 

 dorsal extremity. It increases in size laterally so that its outline presents a 

 tree-like appearance, the branches of which are directed lateralis from the 

 dorsal midline. The nucleus st)on occupies almost the entire area of the 

 column of Coll. 



The nucleus of Burdach appears as a small, sessile condensation in the 

 dorsal surface of the central gray matter, lateral to the base of the nucleus of 

 Goll. It expands rapidly in size and is displaced laterally by the increasing 

 bulk of the nucleus of Goll. The entire dorsal nuclear mass begins to show the 

 ellects of the opening of the fourth ventricle. A marked displacement takes 

 place in the dorsal sensory nuclei, as is c\idenced by the lateral shiftingof these 

 nuclear masses. The nucleus of Burdach becomes arborescent in appearance, 

 Its dorsal surface oxerhangmg the substantia gelatinosa trigemini w Inch lies 

 ventral and somewhat mesial to it. The nucleus of Goll continues upward 

 beyond the opening of the fourth ventricle, forming a part of its lateral mass. 

 .At aboul the caudal level of the fourth \entricle it begins to decrease and it 

 rapidly is submerged from view by the apj:)roximation of the lateral mass of 

 the fourth \entricle and the dorsal aspect of the nucleus of Burdach. This 

 latter nucleus continues upward to a little abo\'e the mid-pomt of the ven- 

 tricle, where it begins to decrease in size and then disappears to gi\ e place to 

 the vestibular complex. This complex extends Lipward in approximately the 

 same topographical relation as that show n successively by the nucleus of Goll 

 and the nucleus of Burdach. 



The substantia gelatinosa trigemini occupies a |)osition w Inch indicates 

 its continuity with the substantia gelatinosa Rolandi of the spmal cord. 

 Passing upward into the oblongata, it assumes its lateral position. In the 

 lower levels the direction of the gelatinous cap is more or less trans\ erse, but 



