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Three new Trematodes found principally in Black Bass. 



By 



Will. S. Marshall and N. C. Gilbert. 



With Plate 15. 



During- tlie spring-, sumnier, and autiimn of 1902 — 1903. a nunibei' 

 €f black bass from the lakes around Madison were examined for 

 parasites, numbers of which were found to occur abundantly in the 

 dififerent parts of the alimentary tract. Forty-seven bass were 

 examined. all of which contained parasites of some kind, tw^enty-eight 

 of the number containing one or more of the Ankes here described. 

 We have found all three species in the same fish, the most common 

 occurrence, however, being several specimens of Asißjia and Leuce- 

 ruthrus in the same host, the third and smallest of the three, 

 Caecincola, being found in but few fish. The fish examined were 

 taken from Lakes Mendota, Monona, and Wingra, a few being pro- 

 cured from Round Lake, Washburn County, Wisconsin. A very 

 large majority of the fish were the large-mouth black bass, Micro- 

 pterus salmoides, a few specimens only of the small-mouth black bass, 

 Micraptenis doJotnieu, being taken. The parasites were killed in hot 

 water, Sublimate or Flemming's Solution, the last method being used 

 only for small specimens. The large specimens were flattened 

 between two slides and mounted whole or sectioned. The fiukes 

 killed in Flemming's were not stained; for the others we used 

 alum-carmine, alum-cochineal, alcoholic-cochineal, borax-carmine and 

 haemalum. 



Zool. Jahrb. XXIX. Abt. f. Syst. 32 



