(4) Europe
Rosa. Revisione dei Lumbricidi. Mem. Acc. Torino, 1893.
(5) Africa
Michaelsen. A series of papers in Mitth. Naturhist. Museum. Hamburg, 1891-1911.
Beddard. Quart. Journ. Micr. Sci., 1890-95.
(6) America
Eisen. Mem. Calif. Acad., 1894-96.
Cognetti de Martiis. Mem. Acc. Torino, 1905-6.
Rosa. Ibid., 1895.
Beddard. In Hamburg. Magalh. Reise, 1895 and Nachtrag to same by Michaelsen.