150 DR. C. E. BEEVOR AND MR. V. HORSLEY ON THE EXCITATION OF THE 
Fig. 4. 
BONNET. 
ORANG. 
L ONGITUDINAL FISSUffE 
Hip 
Knee 
Ankle. 
Haitux 
ShoiAldUr.^, 
jE-iboux ® 
Flne^jrs 
• • ® 
R 
Small 
Toes 
SF 
HaUux 
AitToes ® 
ArU-cie. e 
Knee. 
HifD. 
R 
IP 
e 0 
•ycs s * 
Ffe 
« 
Pc 
9 9 0 
Eyes. 
'peti-. 
9 
9 
« 
0 
9 
• IP 
u> 
0 
Hr 
ye^ 
* 9 9 
AnyU ofV^EoutEL 
9 
Eower\jaj^ * 
SYLVIAN FISSURE 
of * ' 
lift 
*Lovj€r0Jauj: 
SF = Sn 2 )erior frontal sulcus. 
R = Fissure of Rolando. 
G = Genu of ditto. 
Pc = Prsecentral sulcu.s. 
IP = Intrai^arietal sulcus. 
We cannot but feel that the foregoing hg. 4 clearly shows that the general plan ot 
the arrangement of the representation of the segments in the two animals corresponds 
closely, and that tlie variations are rather due to the exaggeration of the sinuosities 
in the gyri of the Orang than to any special characters in that animal. Indeed, if the 
Fissure of Holando in the Orang coidd be drawn out straight, the arrangement would 
be practically identical. 
It is extremely interesting to see that tlie plan of the segments of the lower limb is 
truly horizontal in the Orang, i.e., transverse to the Fissure of PtOLANDO, but antero- 
posteriorly placed in the Bonnet. We believe that this depends upon the following 
considerations, which we venture to suggest are not merely fanciful, and which we 
connect with the great representation in tlie Orang of extension of the hip as 
contrasted with the usual flexion of that joint in the Bonnet. 
The habits of the two animals appear to afford an explanation of the difference of 
the mode of representation in their brains. 
The Bonnet Monkey saves itself in flight by climbing, for which the first purposive 
movement of the lower limb is of necessity flexion of the hip. This, therefore, we find 
represented most anteriorly in the lower limb region, and therefore localised exactly 
