66o THE HIGHER ANTHROPOIDS 



of GoII (NO) surrounded by an encapsulating mass of medullated fibers, 

 the column of Goll (CG). Lateral to this is the proximal portion of the 

 nucleus of Burdach (NB) which projects backward into a massive column 

 of Burdach (CB). Occupying the most lateral portion of the dorsal sensory 

 field, and connected bj' a very narrow strip of gray matter with the central 

 gray, is the substantia gelatinosatrigemini (NR) surrounded on its periphery 

 bj^ the descending trigeminal tract (Trd). 



A comparison of these three nuclear elements in the dorsal field, i.e., 

 the nucleus of GoII, the nucleus of Burdach and the nucleus of Rolando (a 

 term applied to the substantia gelatinosa trigemini), gives an accurate idea 

 of the sensory influx from the deep proprioceptive organs of the body. The 

 column of GoII appears to be about one-quarter the size of the column of 

 Burdach, while the trigeminal area is about one-half the size of the latter 

 bundle. In terms of functional capacity it appears from these relations that 

 the influx of sensory impulses from the leg is considerably less than that 

 from the upper extremity and hand; the influx from the head and face 

 occupies an intermediate position between these two. \\'hen the great size 

 of the gorilla's fore extremity, the tremendous forearm and highly developed 

 hand, is taken into account compared with that of the leg and foot, the reason 

 underlying the increment in the column of Burdach becomes apparent. 

 On the other hand, the innervation of the head and face does not vary much 

 in its relative dimensions as seen in the intermediate primates. It is, however, 

 considerably less in size than in the lower primates. This fact seems to denote 

 that the cephalic dermatomic areas play apart of less importance in directing 

 the animal's locomotion than they do in such forms as depend largely upon 

 sensory differentiation of the head and face for their guidance. 



LEVEL OF THE CAUDAL EXTREMITY OF THE INFERIOR OLIVE (FIG. 299) 



Here the lower tip of this structure appears as a circular mass in the 

 ventrolateral region. The circumference of the section shows even more 



