Heterocotyle scotti n. sp. and H. similis n. sp., two gill parasites of Dasyatis pastinaca, are described. H. pastinacae Scott, 1904, is redescribed from the gills of the same Mediterranean host species. New features concerning haptor morphology are reported. The disposition of the sinuous ridges on the haptor of these three species is discussed. All three species possess a spermatophore. The variation in vaginal anatomy of H. pastinacae leads to the suggestion of a sequence explaining the development or destruction of the spermatophore. The specificity of these parasites and their relationships with Heterocotyle from the Atlantic coast of America are discussed.