During the 2nd zoological expedition in Mexico, organized by the Accademia Nazionale dei Lincei in 1971, three fresh-water Triclads, two epigean and one cave-dwelling, were collected. One of the epigean forms, coming from S. Martin de Xualuca, Estado de Puebla, belongs to the genus Dugesia; its species determination is in progress. The other epigean form, found in Lake Patzcuaro, Estado de Michoacan, is represented by 4 asexual specimens and a sexual one; it may be attributed to the genus Dugesia. The cave planarian, found in the "grutas de Coconà", Teapa, Estado de Tabasco, is unpigmented and eyeless. Its copulatory system shows some features which sharply differentiate it from all other Tricladida Paludicola: the copulatory bursa lies posterior to the penis, the bursal canal runs ventrally and frontwards; the bursa opens to the exterior with a little ventral pore. The description of this planarian, called by Benazzi and Giannini Opisthobursa mexicana n.g., n.sp., is in progress.