Abstract
Light and scanning electron microscopic observations were performed on the oxyurid nematodes belonging to the genus Syphacia collected from the ceca of the laboratory conventional golden hamsters and mice. The nematodes from golden hamsters were identified as Syphacia mesocriceti Quentin, 1971. This species differed from S. obvelata (Rudolphi, 1802) from the mice in the measurements and the morpho1ogy by means of scanning electron microscopy. The morphological characters of S. mesocriceti were as follows. (1) The lateral alae was distinctly observed even in the living worms. (2) The lip was triangular and projected foreword, and the periphery of lip was serrated. (3) Mamelons in the male were composed of the thorn-like processes, and took the shape of a crown.(4) There was no significant difference between the measurements of the eggs of S. mesocriceti and S. obvelata.
