Life Cycle: Some species of Euryhelmis use snails as first intermediate hosts, tadpoles as second intermediate hosts, and mammals, such as cats and muskrats, as the definitive host (AAVP, 2014).
Body 0.3-1.9 mm long, strongly flattened, wider than long and rectangular to pentangular or longer than wide and ovoid. Tegument spined. Ventral sucker with axis inclined anteriorly. Testes one or two. Seminal vesicle elongate, with or without one or two constrictions. Ventrogenital sac permanent. Gonotyl elliptical to reniform, largely parenchymatous, overhangs genital pore. Genital pore anteromedian to ventral sucker. Seminal receptacle canalicular. Uterus confined to left side, or extends full width of body. Eggs 28-34 x 13-15 micrometers. In frog- and salamander-eating mammals; Eurasia, North and Central America. Type species E. squamata (Rudolphi, 1819) Poche, 1926.
Sources: Bray, R.A., Gibson D.I., and Jones, A. 2008. Keys to the Trematoda, Volume 3, p. 128.
American Associate of Veterinary Parasitology. 2014. Euryhelminthidae. http://www.aavp.org/wiki/trematodes-2/trematodes-small-intestine/heterophyidae/euryhelminthinae/euryhelmis-squamula/