24 



POULTRY DTS^EASES 



between the 



lungs 



and passes over the base of the 



space 



heart. Some areas of the mucous membrane of the crop 

 contain mucous glands. The crop is simple in the fowl, form- 

 ing two symmetrical sacs in the pigeon and spindle-formed 

 in ducks and geese. In the pigeon during and shortly after 

 hatching time, in both sexes, it produces a milky fluid which 

 serves as nourishment for the young. The esophagus termi- 

 nates in the stomach. 



Stomach 



Some anatomists call the proventriculus the pars glandula- 

 ris and the gizzard the pars muscularis. The pars glandularis 



b 7 



Fig. 4. Visceral Organs of the Left Side of a Fowl. 

 The left abdominal and thoracic walls have been removed; 4, the proventriculus; 5, 

 gizzard; 6, extreme end of the duodenal loop; 7, pancreas; 8, the small intestines; 12, 

 lungs (it will be noted that the lungs occupy the superior part of tlie thoracic cavity 

 and that there is no distinct pleural sac, but that the lungs push up between the ribs; 

 in fact, the ribs are covered on the inner and lateral sides by the lungs); 12a, the 

 liver; 13, base of the heart; 17, kidney; 18, diaphragm. 



(proventriculus) lies dorsal to, and midway between, the two 

 lobes of the liver, taking an oblique course to the left. It 

 terminates in the gizzard. Its mucous surface is studded ])y 

 papilhi-like projections, which furnish openings to glands of 

 the type of those in the fundus of tlio stomncli of tlie horse 

 nnd othor qiuulnipods. 



Gizzard 



The pars muscularis is round, muscular and flattened ImI- 

 erally and lies to the right and posterior to the proventriculus. 



