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a 
4 
1898-90. | THE ANATOMY OF THE ORANG OUTANG, Ce: 
ugliness of the old Orang is largely due to the existence of these cheek 
and neck pads. They form on each cheek semi-lunar appendages 
covered by the skin. In the dead Orang, Fick described them as tri- 
angular in shape. The free apex of the triangle was at the level of the 
malar bone, whilst the attached base of the triangle extended from the 
top of the frontal bone downwards to the lower margin of the lower jaw 
and face. Fick suggests that it occurs only in old age and in the male sex. 
These masses of fat are, to some degree, mobile; and Fick figures an 
Orang lying asleep, in which the cheek pad having fallen forwards, forms 
a cushion for the creature to rest itshead upon. A similar development 
of fat occurs in the neck of the old Orang. Deniker and Boulart' 
describe similar voluminous pads of fat in the Orang—one 6 cm. thick, 
extended under the occiput and the nape of the neck; two others, in the 
form of semilunar crests 18 cm. long and 11 cm. wide existed on the 
side of the face and upon the jaws, and gave the animal a most 
singular appearance. This development of fat in the Orang appears 
to be connected with the age of the animal, and Fick suggests that 
it is comparable to the accumulation of fat which is apt to occur in 
man after a certain age is reached. 
In my Orang there were no such free appendages of fat, but a mass of 
fat existed beneath the jaw, extending down over the hyoid bone and the 
larynx. Embedded in this were two thin walled sacs which were found 
to communicate with the air passages. They were in fact diverticula 
from the larynx, and were pyriform or egg shaped, attached above in the 
neighbourhood of the thyro-hyoid membrane; they diverged from one 
another, passing out under the sterno hyoid muscles and after appearing 
in the neck on either side at the posterior border of this muscle, they 
came forwards towards the middle line. The sac upon the left side 
measured 5 cm. in its long axis and 2.3 cm. in its greatest width. The 
right sac measured 2.5 cm. long and 1.5 cm. wide. The sacs were very 
readily separated from the mass of fat in which they were embedded. It 
would appear that these sacs occupied an unusual position in my Orang 
in their relations to the muscles. In the descriptions which I have been 
able to consult they are figured as appearing in the middle line of the 
neck between the infra hyoid muscles, whilst in my Orang they passed out 
behind these muscles and appeared at the posterior border of the muscles. 
in the manner described. It is in the median position that Vrolik” des- 
cribes and figures them in the Chimpanzee, as do also Deniker and 
1 J. Deniker and R. Boulart, ‘Sur divers points de l'Anatomie de l’Orang-Outan.” Compte 
Rendus de l’Academie des Sciences. Vol. CXIX, 1894, p. 236. 
2 W. Vrolik, ‘‘ Recherches d’Anatomie comparée sur le Chimpansé,” Amsterdam, 1841, p. 44 and 
plate 2. 
