Discipline: Veterinary Medicine
Adult Cannyerius gregarius (Looss, 1896) Stiles & Goldberger, 1910 and C. mancupatus (Fischoeder, 1901) Stiles & Goldberger, 1910 were examined with a scanning electron microscope. Both species showed transverse and radial folds on their body surface and acetabulum, respectively. Both species revealed the presence of tegumental papillae, which were irregularly distributed on the body surface but aggregated around the oral and ventral pouch openings and sparsely around the acetabulum. Papillae around the oral and ventral pouch openings in C. gregarius were dome-shaped and ciliated on their apices while those in C. mancupatus were dome-shaped with smooth surface. Papillae around the acetabulum in both species were also dome-shaped with smooth surface but smaller than those on the main body surface of C. mancupatus. The two species were compared with other species of the genus Cannyerius and of other genera of the family Gastrothylacidae examined in this manner. The significance of the folds and tegumental papillae is discussed.