24 THE VETERINARY SCIENCE 



cavity. The principal points to be noted in this bone are that it 

 is the softest one in the horse, and that the first eight pairs 

 of ribs are attached to it on either side. This bone, in the 

 horse, resembles a small, flat boat. 



12. Ribs. — There are eighteen pairs of ribs. They form 

 the lateral wall of the thorax or chest cavity and afford pro- 

 tection to the heart and lungs. They are attached above to 

 the dorsal region of the back bone; below, the first eight pair 

 are attached to the sternum, or breast bone ; these are called 

 the true ribs of the horse ; the next ten pair are not attached 

 to the sternum below, the lower ends being free. They are 

 continued downward and forward by a small piece of carti-' 

 lage or gristle, and are just slightly attached to the breast 

 bone; these are called the false ribs. Note that, starting with 

 the first rib, they get longer until the ninth rib is reached ; 

 they then get shorter, the last rib being only a few inches 

 long. 



13. Number of Bones in the Skeleton of a Horse. — 

 Thirty-eight bones are found in the head of a colt, not includ- 

 ing the teeth, but in after life a great many bones become 

 attached to each other by a process called ossification. 



Head 38 



Spinal column 54 



Pelvic cavity or hips, three pair or six sirgle G 



Ribs, eighteen pair 36 



Breast 1 



Both front legs 42 



Both hind legs 38 



Ear, bones very small and unimportant, 3 in each ear. . 6 



Total, not including the teeth 221 



The teeth are dealt with separately in Chapter XV. 



