MOTOR CORTEX AND INTERNAL CAPSULE IN AN ORANG-OUTANO. 157 
Plates 18-20 (Figs. 1-27). 
PLATE 18. 
f^ig. 1. Photograph of the external surface of the left hemisphere, which is tilted 
laterally, so that the genu of the Fissure of Polando is opposite the centre 
of the lens. Natural size. 
Tlie letters refer to the same parts as in fig. 1, Plate IG. 
In figs. 1 to 27, the shading shows the area of representation of the various 
movements, the depth of shading showing the degree of representation. The num¬ 
bering of these figures corresponds to the description in the text (pp. 134-147). 
Figs. 2-27 are photographs of the central convolutions corresponding to fig. 1. 
Fig. 1. Both eyes move conjugately to the opposite side. 
Fig. 2. Combined movement of eyelids opening briskly, eyeballs turning to the o])po- 
site side, and head turning to the opposite side. 
Fig. 3. Bilateral closure of the eyelids, but those of the opj)osite side more strongly 
than those of the same side. 
Fig. 4. Elevation of upper lip of opposite side. 
Fig. 5. Retraction (horizontal) of the opposite angle of the mouth. 
Fig. 6. Eversion of the opposite lower lip. 
Fig. 7. Rolling in of both lips, especially of the lower and of the opposite side. 
Fig. 8. Pursing of both lips. 
Fig. 9. Pouting of both lips. 
PLATE 19. 
Fig. 10. Twitching of the opposite half of the upper 2 )art of the orbicularis oris. 
Fig. 11. Opening of the moutli. 
Fig. 12. Tongue protruded, flattened posteriorly, tip directed to opposite side. 
Fig. 13. Tongue protruded, heaped up on the same side, and tip directed to the 
opposite side. 
Fig. 14. Tongue neither protruded nor retracted, but rolled over to opposite side. 
Fig. 15. Tongue retracted, heaped up posteriorly, and rolled over to opposite cheek. 
Fig. 16. Tongue retracted slightly, flattened throughout, and the tip of the opposite 
side retracted horizontally. 
Fig. 17. Movements of the thumb. 
Fiof. 18. Movements of the index finofer. 
Fig. 19. Extension of the fingers. 
Fig;. 20. Movements of the wrist. 
Fig. 21. Flexion of the elbow. 
