Two new species ofEurycestusClark 1954 are described from the American avocetRecuruirostra americanaGmelin 1788.Eurycestusis a genus of disproportionately wide cestodes in which suckers and rostellum are apparently wanting and which have complete duplication of reproductive system in each segment. The new speciesE. falciformisandE. latissimusspp. nov.differ from E.avocetiClark 1954;E. falciformisresemblesE. avocetias figured in Clark's (1954) plate I, E.latisrimusresemblesE. avocetias depicted in Clark's (1954) plate II, but the three species differ, the diagnostic characters being shape of the strobila, size of the cirrus‐sac, number of testes and armature of the cirrus, the last mentioned being the most easily recognized constant differentiating character.E. latissimusmeasuring up to 33 mm broad, and less than 1 mm in length, has, in each side, 31–44 testes, a cirrus‐sac 333–447 μm long by 45–47 μm in diameter and a cirrus with 14–16 longitudinal rows of strong rose‐thorn‐shaped spines, measuring 7 μm high; whileE. falciformis, 12–20 mm wide by 1.7‐2.4 mm long has, in each side, 27–35 testes, a cirrus‐sac 355‐320 μm long and 43‐35 μm in diameter with a cirrus armed with 20–24 longitudinal rows of slender spines 4.5 μm long. In the holotype ofE. avocetithe cirrus‐sac measures 240–260 μm long by 55‐51 μm in diameter and the cirrus is armed with over 40 longitudinal rows of minute spines 1.5‐2 μm long. It also shows a reticulate uterus but the number of testes cannot be determined in it.A young avocet(R. auosetta)taken in the Camargue in the south of france was found by Baer (1968) to contain free, scolex‐less strobilae which he identified asE. avocetiClark in addition to separate scoleces embedded in the intestinal mucosa. He considered that the scoleces, dilepidid in type, belonged to the free strobilae, which if correct, adds to our knowledge ofE. avocetiC