10 Post, George 1971 Laramie, WY Agricultural Experiment Station, University of Wyoming 24p. January, 1971 animal studies, cestoda (tapeworm subclass), Diphyllobothrium cordiceps, ecology, fish, habitats, invertebrates, lakes and ponds, parasites, westslope cutthroat trout (Oncorhynchus clarki lewisi), wildlife health, Yellowstone Lake, Diphyllobothrium in fis Diphyllobothrium cordiceps is a cestode parasite which exists in salmonid fishes of certain Yellowstone Park lake environments. The parasite is found primarily in the cutthroat trout of Yellowstone Lake, although it has been found in brook trout, rainbow trout and grayling in other lakes of the northern Rocky Mountains. This report contains the following sections: historical background of the parasite in Yellowstone Park; life stages of Diphyllobothrium cordiceps; measurements of Yellowstone Diphyllobothriid cestodes from various hosts; present status of the Diphyllobothriid cestode in Yellowstone National Park; and conclusions. Found at Yellowstone Research LibraryNatureBib ID: 32542