"Look at this picture. It is the skeleton of the snake. That great bone which runs through the whole length of the animal from head to tail is the backbone. Teacher showed us that this is not agood name, for it is really a string of separate bones, and they are joined loosely together in a very wonderful way.
"Each bone has a little round knob or ball infront, and a hollow cup or socket behind. The cupof one ball fits into the socket of the next a n d f o r m s w h a t i s known as a "ball-and- socket" joint. Such ajoint makes the body very flexible, and enables thecreature to bend and twist easily in all directions. "Now let us look at the short cur ved bonesarranged in pairs on either side of the backbone. These are the ribs. I daresay you know that a man has a backbone and twelve pairs of ribs. Look whata number of ribs this snake has. Some snakes have as many as 300 pairs of ribs.
"Teacher next pointed out to us that these ribs are all jointed to the backbone by ball-and-socket joints, and that the lower end of each rib is free to move. They can move easily backwards, forwards, sideways-in every direction.
