THE FROG. 



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sacs opening directly into the larynx ; there is no 

 trachea. 



FIG. 60. 



FROG OPENED FROM BELOW. E, stomach ; C, heart ; c, aortic arches ; P, lungs ; 

 F, liver; R, kidneys; I, large intestine; V, bladder; i, small intestine; ov, 

 ovary; od, oviducts ; I, tongue, turned to one side together with lower jaw. 



The heart has three cavities, two auricles and one 

 ventricle, so that circulation is incomplete, as in reptiles. 



10 



