Comparative surface ultrastructure of adults and eggs of Gnathostoma obtained in Japan

As limited studies have been done on surface morphology of Gnathostoma, adult specimens and eggs of four kinds of species in Japan were compared by scanning electron microscopy. Worms had a subglobular head-bulb which was armed with 7-10 rows of cephalic hooks. Mutidigitate cuticular spines were spaced unevenly on transverse cuticular striations on the anterior half of the body. The lengths of the spines were variable with tridentate spines longer than bidentate ones, These tridantate spines became one of the species specific characteristics. The posterior half of the bodies of G. doloresi and G. hispidum were covered densely with long unidentate spines which were gradually shorter towards the posterior ends. Ventral sides of male terminals had different shape of papillae which so called small and caudal ones in species. Eggs recovered from the uteri of female worms were covered with cuticular pits of different sizes, shapes and depths in species.