272 PROFESSOR OWEN ON THE EXTERNAL CHARACTERS 
soon surpass those of the kinds of Gyrencephala, Lissencephala, and Lyencephala now 
living upon the earth. 
Agreeably, therefore, with the above estimate of the value of cerebral characters, the 
Troglodytes Gorilla, like the T. niger and the Pithecus Satyrus, remains with the Gibbons 
and lower Quadrumana, and stands apart in a distinct subclass from the genus Homo. 
I next proceed to consider the value and application of the characters afforded by the 
limbs of the Gorilla. 
In the terminal segment of the fore limb the pollex is stunted’; the other digits, 
lengthened and strengthened, with their proximal and especially their middle phalanges 
expanded for the support of the broad callosities on which the beast walks: the length 
of these digits enables them also to bend upon the palm and grasp or cling to a bough, 
and the hand is thus adapted for movement in trees, as well as for the quadrupedal 
progression on the ground: but, in the same degree, it is deprived of the faculty of 
delicate digital prehension or “‘ manipulation.” The hand of the Gorilla offers a slight 
advance upon the type of that in the Chimpanzee or Orang by its greater relative 
breadth: the entire fore or upper limb is also rather shorter in proportion to 
the body. Compared with the modifications of that limb in Man and the resultant 
powers of the member, the fore limb of Quadrumana appears to me to be inferior to that 
in Bimana in a greater degree than it is superior to the fore limb in the Squirrel or any 
pentadactyle Unguiculate : the difference between the Gorilla and Man in this particular 
I regard therefore as one of ordinal value. In the lower or hind limb the difference 
between the Gorilla and Man is still more manifest and important in its consequences. 
The deficiency of length in proportion to the trunk is greater than the excess of length 
of the upper limbs. The foot is made a true hand, or grasping organ, by the opposition 
of a thumb to the other digits, as well as by the length and flexibility of the toes*. 
Accordingly the innermost digit presents as well-marked modifications to act the part 
of a ‘thumb’ as affect it in Man in order to act the part of a ‘ great toe’: in both cases 
the whole tarsus has been subject to coordinate modifications®. The other four digits 
in the Gorilla present a greater excess of length compared with Man than in the upper 
limb; they are also more approximated to each other, and are bound together in a 
common ligamentary sheath to nearer their extremities than in Man, and are collectively 
Chimpanzee, affirms :—“ Le cerveau est absolument de la méme forme et de la méme proportion, et il ne pense 
pas: y a-t-il une preuve plus evidente que la matiére seule, quoique parfaitement organis¢e, ne peut produire ni 
la pensée ni la parole qui en est la signe, 4 moins qu’elle ne soit animée par un principe superieur?’’ (Hist. Nat. 
xiv. p. 61.) 
‘ In the Gorilla the length of the entire pollex only equals that of the metacarpal of the middle finger, and is 
rather more than three-eighths the length of that finger: in Man the pollex equals the metacarpal and nearly 
the whole of the first phalanx of the middle finger, and is almost two-thirds the entire length of that finger, 
including the metacarpals in both cases. (Memoir, No. VII., Trans. Zool. Soc. vol. iv. p. 11. pl. 10.) 
* Memoir, No. VIL., pl. 11. fig. 2. > Ib, figs. 1 & 2. 
