Page:Popular Science Monthly Volume 25.djvu/742

724 styloid process is itself prolonged down to the tongue-bone and articulated with it in the fresh state. It is quite a large bone, three and a half inches long (see Fig. 1, A). This arrangement is seen in many of the lower animals, and in them the bone, which is a very important one, is called the epihyal bone.

2. At the base of the skull on the left side, behind the mastoid process, the prominent nipple-shaped process behind the ear, is a stout, bony spur, more than three quarters of an inch long, which has a downward direction, and articulates with the first bone of the vertebral column (see Fig. 1, B). This process is rarely seen in the human being, and is the only one I have met with, but it is quite the normal condition in most graminivorous and carnivorous animals, being especially well marked in the horse, pig, sheep, and goat. In them it is an important part, and gives attachment to strong muscles which move the head on the trunk. It is called the para-mastoid process, from its proximity to the mastoid.

—I suppose every one is aware that the vertebral column, or backbone, is composed of many separate bones, some of which carry ribs. The backbone is made up of thirty-three bones, seven in the neck, twelve in the trunk, five in the loins; below this we have a bone called the sacrum, which consists of five vertebræ fused together; and lower down still four small bones which represent the tail-bones, called, when taken together, the coccyx, from their



supposed resemblance to a cuckoo's beak. Now, each trunk, or dorsal vertebra, has two ribs connected with it, one on each side; so there are altogether twenty-four ribs, twelve on each side; but sometimes