76 PRACTICAL ZOOLOGY. 



10. Make a drawing of the fish as seen from one side, 

 naming all the parts visible. Describe fully all the 

 parts above noted, including the general color and 

 markings. 



DISSECTION OF A PISH. 



Hold the fish with its back in the palm of the left hand, 

 and the tail towards you ; thrust the point of one blade 

 of the scissors obliquely forward through the body-wall, 

 just in front of the anus, and cut forward in the middle 

 line to the ventral fins. After observing the organs with- 

 in, cut upward, i.e., toward the dorsal region of the fish, 

 with scissors, from the beginning of the first cut as far as 

 possible without cutting anything but the body-wall, being 

 especially careful not to cut into the air-bladder which 

 occupies the upper part of the body-cavity ; now cut for- 

 ward to a point a little above the pectoral fin ; make the 

 same cut on the other side; turn forward the flaps thus 

 made, noting the silvery membrane, the peritoneum, 

 lining these flaps, and study the organs of the body-cavity. 



1. In the front part of the body-cavity is a reddish or 

 brownish mass, the liver, lying chiefly on the left side 

 of the fish. Raise the hinder edge of the liver, and 

 observe how closely it fits the organs next to it. 

 Press the liver backward, and observe the hepatic 

 veins passing forward from the liver through the 

 thin partition in front. 



2. Lay the fish on the right side and turn the liver 

 downward, gently tearing away its thread-like attach- 

 ments. This uncovers a pinkish sac, the stomach. 

 Pass a probe back through the mouth and wide 



