360 



THE INTERMEDIATE PRIMATES 



which becomes more prominent as it extends toward the pons, the restiform 

 body. In the cephalic regit)n of this lateral area is another protuberance, 

 the tubercuhim acusticum. 



FIG. 167. LEFT LATERAL SURFACE OF BRAIN, MACACUS RHESUS. 

 [Actual Length 62 mm.] 



Key to Diagram, sulc. occip. lat., Sulcus Occipitalis Lateralis; sulc. prect. inf., Sulcus Precentralis 

 Inferior; sulc. retroct. inf.. Sulcus Retrocentralis. 



The dorsal surface of the oblongata presents its two characteristic 

 divisions, the ventricular and the infraventricular portions. The infraven- 

 tricular portion is directly contniuous with the cervical portion of the spinal 

 cord. As the inferior angle of the fourth ventricle is approached, two slight 

 elevations appear on either side of the dorsal septum. The most mesial of 

 these is the clava, an eminence produced by the presence in the dorsal 

 field of the nucleus of Goll. At a slightly higher level, separated from the 

 clava by the dorsal paramedian sulcus, a second elevation, the cuneus, 

 makes its appearance. Both of these elevations extend cephalad following 

 the general divergence occasioned by the opening of the ventricular space. 

 Of these two elevations, which represent respectively the nucleus of Goll 

 and the nucleus of Burdach, the latter is definitely larger than the former. 

 The significance of this inequality arises from the fact that in macacus, the 

 forelimb and hand, having gained predominance as sensory organs over 



