TEE SPINAL CORE. 
23 
or pouch must resound. Possibly this great bag of air may have some tiling to do with 
making the body lighter when the animal is climbing and using all the force it can with its arms. 
These so-called “ laryngeal ” pouches are found in many Apes and Monkeys, but their double opening 
into the space below the little flap is peculiar to the great Apes, which are sufficiently man-like as to 
be called by the term Anthropoid — the Gorillas, their allies the Chimpanzees, the Orangs, and the 
Siamangs.* All the other Monkeys of the Old World with sacs have but one opening into a space, 
or, as it is termed, the ventricle of the organ of voice, or larynx. The Monkeys of the New 
World have a different arrangement of air pouches, which will be noticed in the proper place. 
The Gorilla has one little peculiarity which distinguishes it from all other Apes and Monkeys, 
and which causes it to be more like man, and insignificant as it may seem, it is of some interest. 
In man there is a decided projection of bone behind, or rather below the ear, and this is called 
the teat-shaped process of the ear-bone (Mastoid process), arid is of importance to the organ of hearing 
and also to the muscles which steady and keep the head erect, and allow of its being moved in par- 
ticular directions. This process exists to a certain extent in the Gorilla but not in the Chimpanzee, 
Orang-Utan, or in any other of the Quadrumana. It is smaller in the Gorilla than in man, but 
it is made up, as in us, of a number of spaces enclosed by bones which have to do with the 
organ of hearing in some way or other, and which are lined with membrane. On the outside a 
muscle is attached, which passes downwards and inwards to the top of the breast-bone, covering 
the great blood-vessels and nerves of the neck. 
In examining this process of bone, attention is of course drawn to the ear itself, and there 
is no doubt of the remarkable resemblance of those of man and of the Gorilla. The great Ape 
has evidently a very quick sense of hearing, for it gets out of the way of men as quickly as is 
possible, when it can only hear them in the forest and jungle, but that it should have the outside 
ear fashioned nearly after the resemblance of that beautiful structure in man is very remarkable. 
The ear of the Gorilla is smaller in proportion to the size of the head than those of other Apes, 
and is about the same length, but broader than that of man ; the lobe, which is perforated by 
us for earrings, is perhaps less perfect in the Gorilla, but all the curves and folds, which are so 
complicated yet so graceful in the human ear exist in it, modified more or less, and not so 
harmonious in their general symmetry, as in man. 
With all its great strength, the head of the great Ape cannot move as readily on the neck 
as that of weaker man, for the skull is not placed on the neck end of the back-bone quite in the 
same manner, and its position is not that which is admirably (as in us) adapted for carrying 
the head erect. One of the greatest marvels in the structure of man is the manner in which 
the tender mass of nerves called the spinal cord or marrow passes out of the hard skull into a bony 
canal down the spine, and yet does not suffer injury as head and back move and roll about. 
The spinal cord or marrow passes out of the skull through a special opening, on the outside of 
which is a joint on either side. These joints fit on to corresponding ones on a ring-shaped bone (atlas bone), 
and this bone rests on one equally hollow, and which has an upward projection which enters the ring 
(axis bone), and is clasped to it by a strong ligament. It is this projection which prevents the spinal 
marrow from being injured by the head moving too freely, and yet life hangs almost on a thread, for 
were this strong ligament to break the soft nerve would be pressed in by the bony projection, and death 
would ensue. All the motions of the head are connected with these bones and their joints, and the way 
in which it is carried is in relation with the position of the opening in the skull for the spinal marrow. 
If the head is to be carried erect, as in a man and in many birds, the opening is far from the back 
part of the head. If the face is to look upwards, as it does in a pig or dog, the opening is very far 
backwards. In the Gorilla it is not quite at the back, but further in that direction than in man, and 
hence the face of this Ape is more liable to be looking upwards than forwards. This is really the case, 
for the natural position of the animal is not erect, but on all-fours, and then it wants to look, not on 
the ground, but upwards and forwards, by tilting the head. Many of the great muscles of the back 
crest have to do with this. It is noticed also that the joint which permits the head to move on the 
ring-shaped bone (the atlas bone) is not so long or curved as in man, and therefore the movements 
of the Gorilla’s head are restricted. 
The Gibbons have no air sacs. 
