8i 



MAN 



assiinu'cl the i-rccl ijostiirc, hv walks upon two left without aid or support 

 from thr upptT cxtrciiiilifs. Such is not the- case m any ol the apes which 

 c'Mi|)lo\' hotli the hands and the leet m their locomotion. E\'en those which 



FIG. 346. M.AN. LEVEL OF THE \ESTIBl LAK NLCLEl. 

 AMB, Nucleus Ambiguus; err, Central Tegmental Tract; do, Dorsal Accessory Olive; dt, Deiterso-spinal 

 Tract; cow. Ventral Spinocerebellar Tract; ici'. Inferior Cerebellar Peduncle; 10, Inferior Olive; mf, Mesial 

 Fillet; NAC, Ventral Cochlear Nucleus; nad. Dorsal Cochlear Nucleus; nd, Deiters' Nucleus; nfs. Solitary 

 Nucleus; nmi', I ly[>oglossal Nucleus; nr. Nucleus of Rolando; NSC, Schwalbe's Nucleus; mo. Vagal Nerve; 

 I'D, Predorsal Bundle; I'l., Posterior I ongitudinal Fasciculus; pv. Pyramid; ref. Reticular Formation; rst. 

 Rubrospinal Tract; si'i, Spinothalamic Tr.ict; trd, Descending Trigeminal Tract: \(i. \entral Accessory 

 Olive. (Accession Man. Section C 7. Actual Size 23 X 9 mm.| 



have acquired something approaching the erect posture do, nevertheless, 

 supplement tlu'ir locomotor actixities by usin<i- tiu- hands either directlx 

 in contact with the (i;r()und or as balancinj^ structuix's held outstretched o\'er 

 the head. An essential dillerenct' also in this connection is that tlu' human 

 hand has lost its foot-like characters while tlu' leet ha\e correspondin<2;ly 

 become diflerentiated as locomotor or<;ans de\ oid ol prelu'iisih' specialization. 



