Figure 8.-- Lemaea tortua, the "anchor worm" of fish (after 

 Wilson). 



large enough to be seen easily. They are 

 found in many organs but some species 

 found in the muscle produce a large ugly- 

 looking "boil." These are not infective for 

 man. 



2. Flukes. Some of the "grubs" discussed 

 in the previous section may be found in the 

 nnuscle. 



Figure d.--Argutus irilineaius, the "fish louse" (after Guberlet). 



3. Tapeworms. A tapew^orm that is con- 

 sidered important because it may infect man 

 through eating improperly cooked infected 

 fresh-water fish is the broad fish tape- 

 worm, /;i;)Ay/io6o«^rium Zoium. The white larva 

 (plerocercoid) may be found among the 

 viscera as well as in the flesh, and may be 

 up to an inch in length, but has no other 

 outstanding characteristics. Normally the 

 parasite ■will attain maturity in the intestine 

 of bears, man, dogs, and perhaps other 

 animals if they eat infected fish (fig. 11). 

 It grows into a large worm - up to 30 feet 

 in length - and produces millions of eggs 

 which pass out with the feces of the animal. 

 If the eggs fall or are washed into the lake, 

 a small swimming larva (coracidium) 

 hatches out. This very active creature 

 develops into the next larval stage (pro- 

 cercoid) when eaten by certain species of 

 "water fleas" (copepods). Small fish feed 

 on the infected copepods, and if a pike or 

 perch eats such fish, the larva will continue 

 to develop. Humans beconne infected by 

 eating raw fish containing the larval stages. 



4. Roundworms (nematodes). The largest 

 one seen in muscle is Kustrongylides (fig. 12). 

 It is a red worm coiled up in a cyst about 

 1/4 inch in diameter and is sometimes 

 seen while dressing a fish. It may also be 

 found in the body cavity. The life cycle is 

 not entirely known, but it is probable that 

 a bird is the final host. 



