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TEXTBOOK OF ZOOLOGY 



stomach. The chicken feeds largely on vegetal food, particularly 

 grain and plant seeds. This food is ground in the gizzard by the 

 muscular activity of the wall crushing it against the sand and gravel 

 which have been swallowed and lodged there. The walls of the 



E SOPHAGUS 

 T RACHEA 



1_EFT UUNG 

 HEART 



GALL BLADDER 

 PROVENTRICULUS 

 Gl ZZARD 

 DUODE NUM 

 PANCREAS 



UARGE IMTESTINE 



VAS DEFERENS 

 ■URETER 



C L O A C A 



Fig. 320. — Visceral organs of male chicken, ventrolateral view. (Drawn by Titus 



Evans.) 



proven triculus are glandular and secrete gastric juice which softens 

 the food and begins digestion of the protein. The cro'p, which is 

 a modification of the esophagus, is used as storage space for food as it 

 is ingested. In the pigeon the crop is glandular and secretes "pigeon 



