[A comparison of the superficial argentophilic structures of miracidia from 12 species of the genus Schistosoma].

Observation of miracidia of twelve species of Schistosoma shows the fundamental epidermal cell pattern is: 6, 9, 4, 3. Comparison of superficial argentophilic organites permits us: --to divide these species into three inequal groups: mansoni group: Schistosoma mansoni, S. rodhaini. haematobium group: S. haematobium, S. bovis, S. indicum , S. intercalatum, S. margrebowiei , S. mattheei, S. nasale and S. spindale . japonicum group: S. japonicum, S. incognitum . --to emphasize the relatively narrow specificity between members of each group and the snail-hosts. --to position the above species of Schistosoma within the Schistosomatoidea . Furthermore this character gives us some idea of the degree of evolution of species of Schistosoma.