Scanning electron microscope study of radulae in Haliotis asinina Linnaeus, 1758 and Haliotis ovina Gmelin, 1791 (Gastropoda : Haliotidae)

The middle parts of the radula ribbon of 10 mature snails of Haliotis asini na and Haliotis ovina were studied by scanning electron microscopy. In each transverse row, the numbers of the central and lateral teeth of H. asinina and H. ovina are 1 and 10, respectively. The number of the marginal teeth of H. asinina and H. ovina ranges from 108 to 128 and 214 to 236, respectiv ely. The central and lateral teeth of Haliotis spp. are unicuspid. The marg inal teeth of Haliotis spp. are multicuspid. In H. asinina, the anterior cu sps are broad, shea, and blunt ended in the central and first lateral teeth ; long, narrow, and tapered in the second lateral tooth; spade shaped in th e third to fifth lateral teeth; and with one large central and several late ral denticles on the marginal teeth. The radula morphologies of H. asinina and H. ovina are basically the same, with the differences in the middle par t of the base of the central tooth, the size of the central tooth, the shap e of the first and second lateral teeth, and the shape of the lateral denti cles of the marginal teeth.