Three Freshwater Species of Mayorella (Amoebida) with a Cuticle

Mayorella penardi PAGE, 1972 (= Amoeba spumosa sensu PENARD, 1902), M. vespertilioides, n. sp., and M. cantabrigiensis n. sp., all from freshwater, are covered with a cuticle of the same construction as that of M. viridis and two recently described marine species. The first indication of such a cuticle on M. penardi was an electron micrograph by Cigada Leonardi (1958), but its significance was not appreciated at the time. All three of these freshwater species have paired inclusions resembling those of M. bigemma ( Schaeffer, 1918), type-species of Mayorella, and that generic name is tentatively retained for such cuticle-bearing amoebae. Details of the fine structure of M. vespertilioides resemble those of marine cuticle-bearing amoebae.