The purpose of this study was to recollect the non-segmented tapeworms (Caryophyllidea:Cestoidea) reported by Linton (1893, Report U.S. Comm. of Fish and Fisheries for 1889 to 1891; 545-564) from Catostomus sp. In Yellowstone Park, and Bangham (1951, Zoologica 36:213-217) Catostomus fecundus and Gila atraria in the upper Snake River drainage. Since there is some question concerning the taxonomic status of these tapeworms new collections were desirable. Project Number 134.