io8 A GUIDE FOR THE STUDY OF ANIMALS 



and a small chamber, pericardial chamber, between the 

 gill chambers. 



2. Liver, a large red or pink mass lying at the front 

 end of the abdominal cavity, and divided into two unequal 

 lobes. The gall-bladder, thin-walled and green, may be 

 seen between these lobes. 



3. Alimentary canal. 



a. Motith. 



b. Esophagus, in the fish a very short tube. 



c. Stomach, white and muscular, beginning with 

 a very short esophagus and ending as a blind sac. 

 If it is much distended, open it to see what the fish 

 may have eaten. 



d. Small intestines, thin-walled, tubular, and some- 

 what coiled. 



e. Large intestine, a short, thin-walled expansion 

 at the posterior end of the small intestine ; usually 

 less than half an inch long. 



f. Cceca, from two to several small pouches 

 attached where the small intestine leaves the 

 stomach. 



4. Spleen, a reddish brown globulehetneen. the folds of 

 the intestine. 



5. Swim bladder, an elongated chamber lying against 

 the backbone, partitioned off from the cavity below by a 

 delicate membrane. 



6. Peritoneum, the delicate, silvery membrane which 

 lines the abdominal cavity and enfolds the viscera. Note 

 its spots of pigment. 



7. Pericardial chamber, the chamber around the heart ; 

 see § I above. 



8. Heart. As the fish is placed belly upward in the pan 

 the ,ventricle faces you, pink, conical, and muscular. 



