Diagnostic atlas for the identification of helminthic eggs in non-human primates. (a) Hymenolepis nana egg (×100): round to oval of 30–50 μm in diameter containing an hexacanth embryo with equatorial polar filaments; (b) Strongyloides sp. egg (×100): oval, symmetrical of 40–70 μm by 20–35 μm with a thin membrane and parallel lateral sides; larvae can be present inside the egg; (c) Trichurid egg (×100): oval, symmetrical of 50–80 μm by 20–40 μm with a smooth outer membrane and polar plugs striated perpendicular to the axis of the egg; (d) Strongylid egg (×100): oval of variable size with a thick outer membrane, asymmetrical lateral sides and containing a morula; (e) Capillariid egg (×100): oval, symmetrical of 50–80 μm by 20–40 μm with a smooth outer membrane and polar plugs striated parallel to the axis of the egg; (f) Oxyurid egg (×100): oval, slightly asymmetrical of 50–60 μm by 20–30 μm with one flat lateral side, a thick outer membrane and a vermiform embryo.