MAMMALS 219 
vertebre fused together, forming a solid mass for the attach- 
ment on either side of the hip-bones. 
The ribs are borne by the chest vertebree—most of 
them curve round and unite with the sternum or breast- 
bone in such a way as to form a cavity in which the 
organs of the chest are protected. 
The fore-limb. The upper part of the forelimb 
consists of a single long bone (the humerus) the upper end 
of which is rounded and works in a hollow socket at the 
front end of the shoulder-blade—a flat triangular bone 
overlying the chest. Connected with the humerus by 
blade 
Shoulder 
Fig. 126.—The Rabbit showing skeleton, or bony framework. 
means of a hinge joint are the two lower arm bones (the ulna 
and radius) placed side by side. Below these are two rows 
of small wrist bones (the carpals), and further on five rod- 
shaped bones (the metacarpals or bones of the palm). ‘The 
fore-limb ends in four jointed digits or fingers. 
The hind-limb. The upper part of the hind-limb 
consists of a single bone (the femur), the rounded end of 
which works in a cup in the hip-bone. Below the femur 
and forming with it a hinge joint, are the two bones of the 
lower part of the leg (the tibia and fibula). These differ 
from the corresponding bones of the fore-limb by being 
fused together at the lower ends. Below these are the 
