Braun, in Bronn's Klassen u. Ordn. d. Thierreichs, vol. iv. p. 407, gives a valuable summary of our knowledge of this group. For figures, see van Beneden and Hesse, Mémoires de l'Acad. roy. de Belgique, tom. xxxiv. 1864, pp. 1-169. A valuable paper (with synoptic tables) on Japanese Monogenea, by Goto, Journ. Coll. Sci. Japan, vol. viii. pt. 1, 1894, has recently appeared.
See Leuckart, "Parasiten" Bd. ii. p. 238.
Zeller, Zeitschr. f. wiss. Zool. xxii. 1872, pp. 1, 168; also Bd. xxvii. 1876, p. 238; xlvi. 1888, p. 233.
An excellent and beautifully illustrated account, by Looss, of the Distomatidae of Frogs and Fishes may be found in Leuckart and Chun's Bibliotheca Zoologica, Heft 16, 1894.
Leuckart, Parasiten d. Menschen, "Trematoden," 1892-94; R. Blanchard, Traité d. Zool. médicale, i. 1889; H. B. Ward, Report for 1894 of Nebraska State Board of Agric. Lincoln, U.S.A. 1895, p. 225.