Three species of Myxobolus (Myxozoa, Myxosporea) occur in heart tissue of centrarchids. Myxobolus paralintoni Li and Desser, 1985 from Lepomis gibbosus in Algonquin Park and in Lake Erie, Ontario, has subcircular spores (in plane of spore length) in frontal view (11-13 microm long, 9-10 microm wide, and 5 microm thick) with a width-to-length ratio of 1:1.2. Myxobolus jollimorei n. sp. from Lepomis macrochirus in Lake Erie and in the Pascagoula River System, Mississippi, has subcircular spores (in plane of spore width) in frontal view (10.0-11.5 microm long, 12.0-14.5 microm wide, and 6.5-8.0 microm thick) with a width-to-length ratio of 1:0.8. Myxobolus manueli n. sp. from Pomoxis nigromaculatus in Lake Erie has spores (10-11 microm long, 8-10 microm wide, and 6.5-7.0 microm thick) that are nearly circular in frontal view but that have 2 distinct sublateral knobs along the sutural ridge and a width-to-length ratio of 1:1.2. All 3 species occur in the bulbus arteriosus of their hosts where they form small, saucer-shaped pseudocysts. Free spores were found free in the lumen of the heart and bulbus arteriosus, in bile, and in kidney tissue presses.

Myxobolus mississippiensis n. sp. is described from gill lamellae of the bluegill (Lepomis macrochirus) inhabiting the Pascagoula River System, Mississippi. Fresh spores measure 16.4-18.7 micro-m long, 3.9-6.2 micro-m wide, and 4.7-6.2 micro-m thick. Spore width to length ratio is 1:3.2. Polar capsules are 5.5-7.8 micro-m long and 1.5-2.3 micro-m wide, with 9-10 filament coils that when extruded measure 42.1 ± 4.2 micro-m. This parasite is unique among known species of Myxobolus in having spores that are lenticular in frontal view.

The geographic distribution of metazoan parasites of American eels (Anguilla rostrata) was determined from 28 sites in the Southern Upland and adjacent regions of Nova Scotia. Twelve parasite species were encountered. Component community diversity as measured by species richness, Shannon-Wiener index (H') and Hill's number (N1) decreased when pH 5.4. Seven species (Azygia longa, Crepidostomum brevivitellum, Bothriocephalus claviceps, Proteocephalus macrocephalus, Paraquimperia tenerrima, Echinorhynchus salmonis, Ergasilus celestis) were found in both the Southern Upland and adjacent watersheds to the north. Three species (Pseudodactylogyrus anguillae, Diplostomum sp., Pomphorhynchus bulbocolli) were found only at sites beyond the Southern Upland, which flowed into the Bay of Fundy and had high pH values (5.4). Two species (Daniconema anguillae, Echinorhynchus lateralis) were limited to sites within the Southern Upland. Digeneans were absent from rivers in the southwest with pH values