MOTOR CORTEX AND IXTERXAL CAPSULE TN AX ORAXG-OUTAXG. 137 
it is most interesting to observe that its representation was nearer than that of 
pursing to the Fissure of Rolando, passing round its lower end to reach towards tlie 
square in which eversion is most represented. Pouting was observed at squares :— 
(a) In front of Fissure of Rolando, 87, 88, 89, 90. (h) Behind Fissure of Rolando, 
91, 92, 93, 94. 
The focus was situated at No. 90, and the representation decreased from this })oinl 
to No. 87, and as far as to No. 94 behind the Fissure of Rolando. See fig. 9, Plate 18. 
(10) Twitching of the opposite half of the upper part of the Orbicularis Oris .— 
This remarkably specialised movement was restricted to the small triangular area 
lying between the upper end of the secondary sulcus in the foot of the ascending 
parietal gyrus, and reaching nearly to the genu of the Fissure of Rolando, viz., at 
squares 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, and was most marked at the 
vertical line passing through the middle of this region, viz., at squares 130, 134, 136. 
See Plate 19, fig. 10. 
In passing to the next group of movements a prefatory explanation is needed of 
our use of the term, movements of the mouth. By such term we wish to imply the 
opening and closure of the oral cavity, i.e., lowering and raising of the lower jaw. 
Although we shall show that the lower jaw may be occasionally depressed within the 
closed lips, but that, if combined with compression of the lips, the mouth may remain 
shut, it is nevertheless more convenient and in accordance with general usage that 
the mandibular movements and the opening or closing of the labial fissure should be 
considered together. 
Contrary to that which we had observed in the Bonnet {Macacus sinicus), in the 
Orang we never obtained evidence that the movement of mastication was represented 
in the cortex. We, of course, only credit this fact with the value generally attached 
to negative evidence. The various combinations of movements associated with the 
opening of the mouth we will consider in the chapter on the “ Marches ” observed, 
see p. 146. 
(11) Opening of the Mouth .—This fundamentally important movement we found 
to be represented, exactly as in the Bonnet Monkey, at the foot of the ascending- 
frontal and parietal gyri, around the lower end of the Fissure of Rolando, viz., at 
squares (a) in front of Fissure of Rolando, 20, 21, 22, 84, fb) behind the Fissure of 
Rolando, 91, 92. 
It is universally well marked in the squares in front of the Fissure of Rolando, 
but only moderately in those which lie behind it (at 91, 92). See Plate 19, fig. 11. 
Movements oj the Tongue. 
We have found in the Bonnet Monkey (in some experiments shortly to be 
published) that the movements of the tongue are highly differentiated in cortical 
representation, constantly localised in the same position, and arranged in a definite 
order of grouping. The movements of the tongue that we have found to be dis- 
MDCCCXC.-B. T 
