170 



FIRST BOOK OF ZOOLOGY. 



Cavity below, contain- 

 ing lungs, heart, 

 stomach^ etc. 



FIG. 151. A YEKTEBRA AND A PAIR OF BIBS, FROM A CAT CS, Cavity for Cerebro-spinal 



Cord. 



152. If we compare the hind-leg of the salamander with 

 our own leg, we shall find essentially the same arrangement 

 of parts, namely: the leg bending at a joint in its middle, or 

 the knee-joint, and below this joint another one called the 

 ankle-joint. In that portion of the leg above the knee-joint 

 there is one long bone called the femur which joins or articu- 

 lates with the pelvic arch. In the leg below the knee-joint 

 there are two long bones side by side, called the tibia and 

 fibula. In the ankle-joint there are a number of small 

 bones closely packed together; these are called the tarsal 

 tones, and together form the tarsus. In the body of the 

 foot there are several bones upon which the toes rest, and 



