take to
the erect posture. Mr. George Bennett, [16] a very excellent observer,
in describing the habits of a male 'Hylobates syndactylus' which
remained for some time in his possession, says: "He invariably walks in
the erect posture when on a level surface; and then the arms either hang
down, enabling him to assist himself with his knuckles; or what is more
usual, he keeps his arms uplifted in nearly an erect position, with the
hands pendent ready to seize a rope, and climb up on the approach of
danger or on the obtrusion of strangers. He walks rather quick in the
erect posture, but with a waddling gait, and is soon run down if, whilst
pursued, he has no opportunity of escaping by climbing.... When he walks
in the erect posture he turns the leg and foot outwards, which occasions
him to have a waddling gait and to seem bow-legged."

Dr. Burrough states of another Gibbon, the Horlack or Hooluk: "They
walk erect; and when placed on the floor, or in an open field, balance
themselves very prettily, by raising their hands over their head and
slightly bending the arm at the wrist and elbow, and then run tolerably
fast, rocking from side to side; and, if urged to greater speed, they
let fall their hands to the ground, and assist themselves forward,
rather jumping than running, still keeping the body, however, nearly
erect."

Somewhat different evidence, however, is given by Dr. Winslow Lewis:
[17]

"Their only manner of walking was on their posterior or inferior
extremities, the others being raised upwards to preserve their
equilibrium, as rope-dancers are assisted by long poles at fairs.
Their progression was not by placing one foot before the other, but
by simultaneously using both, as in jumping." Dr. Salomon Muller also
states that the Gibbons progress along the ground by a short series of
tottering jumps, effected only by the hind limbs, the body being held
altogether upright.

But Mr. Martin (l. c. p. 418), who also speaks from direct observation,
says of the Gibbons generally:

"Pre-eminently qualified for arboreal habits, and displaying among the
branches amazing activity, the Gibbons are not so awkward or embarrassed
on a level surface as might be imagined. They walk erect, with a
waddling or unsteady gait, but at a quick pace; the equilibrium of the
body requiring to be kept up, either by touching the ground with the
knuckles, first on one side then on the other, or by uplifting the arms
so as to poise it. As