1 1 8 Practical Zoology. 



1 6. Just before the intestine ends, it widens, forming the 

 cloaca. 



17. Turn the gizzard to the right of the bird; entering it 

 from the front, find a mottled, bulging tube, the glandular stom- 

 ach; pull the crop forward, to shew the connection between it 

 and the glandular stomach. To the right of the glandular 

 stomach is the small, red spleen ; pull the gizzard backward, and 

 cut off the glandular stomach as far forward as possible ; remove 

 the gizzard and intestines. Note the relations of the tubes 

 which enter and leave the gizzard ; open the gizzard, observing 

 the thick outer muscular coat, from which the gizzard is some- 

 times called the muscular stomach. Note also its tough lining; 

 examine the contents of the gizzard ; why does the gizzard have 

 such a thick coat of muscle ? Do all birds have this kind of 

 gizzard ? 



1 8. In front of the liver is the heart, in a thin sac, the pericar- 

 dium. Cut into its posterior wall, and turn the heart forward, 

 to see the dark vein, the postcaval vein, running to it from the 

 liver ; pull the heart backward, to see the whitish arteries running 

 forward from it. The main artery runs forward, and turns to 

 the right before going backward, while in man the corresponding 

 artery turns to the left. Prick a hole in one of the large veins 

 near the heart ; insert the point of a blowpipe, and inflate the 

 heart ; its red, conical part is composed of the ventricles ; the 

 dark base is made up of the two auricles. Tie a thread around 

 the veins at the anterior and posterior borders of the liver, and 

 cut this organ away. 



19. On each side are the pink lungs. Pick away the thin 

 membranes bordering the outer hinder borders of the lungs ; 

 look for holes through which the lungs communicate with the ab- 

 dominal air sacs ; look for the trachea. Remove the lungs, not 

 failing to see how closely they are attached to the back, being 

 indented by the ribs. 



20. In the hinder part of the body cavity are the dark- 

 colored, irregular kidneys. Tear them away, observing how 



