Chap. 34 



AMPHIBIANS 



695 



Pericardium 



Pericardium 



Septum 

 Lung 



Pleural 

 cavity 



Liver 



Peritoneal 

 cavity 



Pleuroperifoneal 

 cavity 



Fig. 34.13. Outlines of the body cavities of frog and man. A, in the frog, the 

 pericardial cavity contains the heart; the pleuroperitoneal cavity contains lungs, 

 alimentary canal and associated glands, and reproductive organs. There is no dia- 

 phragm. B, in man; the pericardium contains the heart; the thoracic cavity is 

 divided into two pleural cavities, each holding a lung; the abdominal cavity is 

 separated from the pleural cavities by the diaphragm. 



Storage, digestion, and absorption of food are carried on by the stomach 

 and intestine (Fig. 34.16). The stomach is a pouch for temporary storage. 

 Muscles in its walls squeeze and mix the food, and cells in the lining secrete 

 the gastric juice, which begins the chemical break-up of proteins. Stomachs 

 are not essential to life, but wild animals must eat when food is available and 

 temporary storage in the stomach is important. Frogs may find a pond swarm- 

 ing with mosquitoes on one day and none the next. While food is being mixed 



Kidney 



Gonad 



Peritoneol 

 lining 



RELATION OF PERITONEAL LINING 

 TO ABDOMINAL ORGANS 



Fig. 34.14. Cross section of the body of a male frog taken through the 

 abdomen showing the peritoneal cavity and the kidneys. The peritoneum covers 

 them as it does the other abdominal organs. 



