FISH ENTOZOA FROM YELLOWSTONE PAKK. 561 



larger specimen was brownish red. They are also much like tlie speci- 

 mens mentioned below from the sucker. » 



CATOSTOMUS ARDENS. 



But one species of nematod was found in this fish. These were slender 

 wiiite worms, found in the intestine of their host, where they were 

 associated with Eehlnorhijnrhus (jl<>hiiIo,si(,s and MoxoboiJirinm terebrans. 

 They were from 6 to 8 mm. long and about 0.3 mm. in diameter. They 

 taper toward each end alike. The body in alcoholic specimens appears 

 to be marked with fine longitudinal strite. The lateral lines are promi- 

 nent. When treated with glycerin fine transverse stria* l)ecame visible. 

 The lips are not well defined, but are apparently three in number, m ith 

 several minute papilhe. The reproductive organs are rudimentary. 



In the absence of distinct characters, it is of necessity impossible to 

 refer these larval nematods to established species. 



Washington and Jefferson College, 



Wafshiii(/t<m, Pa., April 3, 1891. 



H. Mis. 113 36 



