44 TREMATODES OF THE PACIFIC NORTHWEST 



Family OPECOELIDAE 



Opecoelina radifistuli (Acena, 1941) Manter, 1947 



Synonym : Dideutosaccus radifistuli Acena, 1941 



Host : Sebastodes elongatus Wash. Acena, 1941 



Not known outside of the Pacific Northwest. Life histories in this genus are 

 not known. 



Opecoelina theragrae Lloyd, 1938 



Hosts : Theragrae fusensis Wash. Lloyd, 1938 



Sebastodes maliger Wash. Ching, 1960b 



Not known outside of the Pacific Northwest. Life histories in this genus are 

 not known. 



Pseudopcoelus vulgaris (Manter, 1934) Van Wicklen, 1946 



Synonym : Cymbe phallus vulgaris Manter, 1934 



Host : Lycodopsis pacifica Wash. Lloyd, 1938 



Additional hosts from Florida were reported by Manter (1934). No life his- 

 tory is known for this genus. 



Plagioporous siliculus Sinitsin, 1931 



Hosts : Salnio clarkii Ore. Sinitsin, 1931a 



"Species of fresh water Ore. Sinitsin, 1931a 



fishes" 



Morphology: All life history stages have been outlined by Sinitsin (1931a). 

 There are no other discussions of this worm. 



Biology: Sinitsin (1931a) stated that sporocysts produce cotylomicrocercous 

 cercariae in the digestive gland of Oxytrema silicula and that the cercariae 

 actively penetrate crayfish where they encyst. The crayfish are eaten by the 

 definitive host. Metacercariae often are so mature that eggs can be seen in 

 them. Sinitsin stated that cercariae stand on their tails waving to and fro 

 (a condition which we have frequently observed), and that when a crayfish 

 passes near them, the cercariae bend toward the crayfish (a response which 

 we have been unable to confirm). We have been unable to complete the life 

 cycle as outlined by Sinitsin. Sinitsin did not prove the life cycle experi- 

 mentally. 



PlagiopoTUS virens Sinitsin, 1931 



Hosts : Cotius sp. Ore. Sinitsin, 1931a 



"Fresh water fishes" Ore. Sinitsin, 1931a 



Morphology: Sinitsin described all the stages of the life cycle. 



Biology: Sinitsin (1931a) .stated that cotylomicrocercous cercariae develop in 

 sporocysts in the liver of the stream snail Flumcnicola virens. The cercariae 

 behave similarly to those of P. siliculus, but they encyst in the snail F. virens. 

 Each snail is usually infected with only a few metacercariae. Sinitsin did not 

 prove this cycle experimentally. 



