The present study showed that some lizardfishes collected from the Suez Gulf were infected with the intestinal cestode Oncodiscus sauridae. Ultrastructural examinations of O. sauridae mature proglottids revealed ten characteristic types of microtriches dressing the external surface of tegument (acicular, papilliform, spiniform, capiform, digitiform, columnar, lingual, tusk- shaped, vial- shaped and thorn-shaped).The syntegument is stacked on a thin basal lamina and inhabited with light membrane-bounded vesicles, dense bodies lacking a limiting membrane, ovoid mitochondria and convoluted secretory ducts ended with rounded reservoirs. Delicate cytoplasmic bridges and thin fibrous layer anchored the syntegument with underlying perikarya. The muscular network was arranged down syntegument in four (circular, longitudinal, ventral and diagonal) distinct orientations. Flame cells were connected with internal cytoplasmic ribs, their luminal cilia (about 100) were confirmed by many elongated rootlets and their excretory ducts were lined with enormous microvilli. Diverse mesenchymal cells (myocytons, tegumental, perikaryal, glandular and calcareous) embedded in the parenchymal were precisely described