MAMMALIA 



285 



specimen and care taken that there is sufficient liquid 

 to fill the space between the slide and cover glass. By 

 pulling on the muscles in the lower part of the limbs it 

 may be seen that those on the back side bend the digits 

 and are therefore called flexors, while those on the front 

 side straighten the digits and are accordingly named ex- 

 tensors. Those muscles attached to the upper limb regions 

 pulling them outward are the abductor -s, while those draw- 

 ing them inward like the great breast muscle are adductors. 



Brain 



Spleen* 

 Stomach \AovtaJena.Cava 



Des. 

 Mon 



Esophagus 1 rv ^ 



Heart 



Liver 



\ n Jquntun, 

 Duodenum 



FIG. 322. Diagram of the chief organs of a mammal. The bones are black, a, 

 opening from the nasal cavity s to pharynx ; bl, bladder ; ce, caecum ; di, dia- 

 phragm ; e, epiglottis ; n, nostril or anterior nares ; ov, ovary ; rf and ute t 

 uterus ; ru and lu, ureters ; x, pancreas ; vag, vagina. From Davison's " Mam- 

 malian Anatomy." 



By cutting away the thin layer of muscle forming the 

 ventral wall of the body cavity the internal organs may 

 be examined. The diaphragm, a thin plate of muscle, 

 divides the thoracic cavity containing the heart, trachea, 

 lungs, and esophagus from the abdominal cavity contain- 

 ing the stomach, intestines, the large dark red liver com- 

 posed of several lobes adjacent to the diaphragm, the 

 pinkish-white pancreas lying along the bend of the intes- 



