Phagicola nana is resurrected from synonymy and redescribed based on syntypes from the arctic fox, Alopex lagopus, and adults from an experimental infection in the Virginia opossum, Didelphis virginiana. Natural definitive hosts include the great blue heron, Ardea herodias; least bittern, Ixobrychus exilis; and possibly gannet, Morus bassanus. The Virginia opossum, northern raccoon, laboratory white mouse, Syrian hamster, and domestic chicken serve as experimental definitive hosts. Natural metacercarial infections by P. nana occurred in the largemouth bass (Micropterus salmoides), redear sunfish (Lepomis microlophus), bluegill (L. macrochirus), and orangespotted sunfish (L. humilis) collected in estuarine bayous and rivers of Mississippi, Florida, and Georgia. Metacercariae caused minor histopathological alterations in fish hosts by inducing formation of fibrotic host capsules. They encysted primarily in sites already containing fibroblasts. Phagicola nana may have broad host specificity for piscivorous birds and mammals inhabiting estuarine marshes. Moreover, humans probably may become infected with P. nana by ingesting raw or inadequately prepared centrarchid fishes. Phagicola nana (Ransom, 1920) was originally described from a single specimen of the arctic fox, Alopex lagopus (Linnaeus) (as Vulpes 1.). Cause of the fox's death in 1906 at the National Zoological Park, Washington, D.C., was diagnosed as intense purulent peritonitis and septic metritis. At necropsy, Dr. H. W. Graybill collected specimens of it and P. longa (Ransom, 1920), and Ransom (1920) described them both. Because the fox was born and lived its entire four years at the Park, we assume it acquired both heterophyids from raw fishes fed to it. Metacercariae of P. longa parasitize mullets (Edwards & Overstreet, 1976; Hutton, 1957; Hutton & Sogandares-Bernal, 1958, 1959, 1960; Skinner, 1975), and adults occur at least in Procyon lotor (Linnaeus) and birds along the Atlantic and Gulf of Mexico coasts (Harkema & Miller, 1962, 1964; Hutton & Sogandares-Bernal, 1960; Overstreet, 1978). This paper is the first to report metacercariae of P. nana, a species that we consider distinct from P. angrense (Travassos, 1916). We found metacercariae of P. nana commonly We thank Sybil Hamlet, Historian, National Zoological Park, Smithsonian Institution, Washington, D.C., for providing information concerning the type-host of Phagicola nana and John C. Pearson, University of Queensland, for commenting on the manuscript. Also, Dr. J. Ralph Lichtenfels loaned us type and voucher specimens of heterophyids from the USNM Helminthological Collection; Dr. Jeffrey M. Lotz and Mr. Larry Shults donated heterophyids collected from birds and mammals in Ocean Springs, Mississippi; Dr. Adrian Lawler provided laboratory-reared chickens and collected raccoons and opossums for us; and Ronnie Palmer, Joan Durfee, and John Lamb provided technical assistance. We acknowledge the University of Wisconsin-Eau Claire for providing a Faculty Improvement Grant to WFF. The study was conducted in cooperation with the U.S. Department of Commerce, NOAA, National Marine Fisheries Service, under PL 88-309 Project Nos. 2-382-R and 2-393-R. 2 Department of Biology, University of Wisconsin-Eau Claire, Eau Claire, Wisconsin 54701,