The endohelminth species common to white suckers from Bellamy and Oyster Rivers were Triganodistomum attenuatum Mueller and Van Cleave 1932 (Trematoda: Lissorchiidae); Glaridacris catostomi Cooper 1920, G. laruei Lamont 1921, Isoglaridacris bulbocirrus Mackiewicz 1965 (Cestoda: Caryophyllaeidae); and Pomphorhynchus bulbocolli Linkins in Van Cleave 1919 (Acanthocephala: Pom- phorhynchidae). Octospinifer macilentus Van Cleave 1919 and Neoechinorhynchus cristatus Lynch 1936 (Acanthocephala: Neoechinorhynchidae) were unique to Bellamy and Oyster River white suckers, re- spectively. Parasite community diversity was not significantly higher in Oyster River (0.533) than in Bellamy River suckers (0.510). Individuals of the species of parasites in Oyster River hosts were more evenly distributed (had a higher equitability) but had a lower mean number of species present (species density) than did parasites of hosts from Bellamy River. Community diversity was highest in hosts from Oyster River in spring and summer 1975, winter 1975-1976, spring 1976, and winter 1976-1977. In white suckers from Bellamy River, diversity was highest in spring 1975 and winter 1975-1976. The middle to posterior intestinal areas of hosts from Bellamy and Oyster Rivers had higher diversity values than did other intestinal areas. There was no significant increase or decrease of parasite diversity with increase in length of host at the Bellamy and Oyster Rivers. There were no significant differences in diversity values between male and female white suckers at either locality. to the laboratory alive, measured (total length in centimeters), sexed, and necropsied within 36 hr of capture. The entire intestine (after the esophagus to the vent) was removed. It was divided into five segments based on percentages of the total length from the anterior end (0-20%, 20-40%, 40-60%, 60- 80%, and 80-100%). These segments were desig- nated 1, 2, 3, 4, and 5, respectively. The position and number of individuals of each helminth species recovered from each segment were recorded. The rivers and sampling procedure were described in Muzzall (1980a, b, c). The Shannon-Weaver formula (Shannon and Weaver, 1949) was used to measure the diversity of the parasite communities. This diversity index (H') is influenced both by the number of species present (species density) and by the actual numbers of in- dividuals of each species in the sample. Equitabil- ity was calculated by the equation E = H'/max (Shel- don, 1969), where Hmax is the natural log of the number of observed species. Diversity and equita- bility values were calculated for individual fish.