296 



INTEOPUCTION TO ZOOLOGY. 



few know that the gizzard is actually the stomach itself, 

 which, thickened in its coats, performs the same office as the 

 teeth of the graminivorous quadrupeds. 



i 



Fig. 248.— Digestive Apparatcs of a Fowl.* 



The action of the gizzard is expedited by small pebbles 

 and other hard substances swallowed by the fowl. In the 

 Ostrich (Fig. 249), this instinctive action prevails to such an 



* e, oesophagus; C, crop; », ventriculus snccenturiatus • g, gizzard; /, liver; 

 Squall-bladder; b, bile-ducts; ;>, j'i""-Teas ; rf, duodenum; c, cceca ; «, sm;i]l intes- 

 tine; L, large intestine: 0, oviduct. 



