The following memoirs will be found useful for further study of this portion of the subject:—
D. Barfurth, Ueber den Bau und die Thätigkeit der Gasteropodenleber: Arch. Mikr. Anat. xxii. (1883), pp. 473–524.
Th. Behme, Beiträge zur Anatomie und Entwickelungsgeschichte des Harnapparates der Lungenschnecken: Arch. Naturges. iv. (1889), pp. 1–28.
R. Bergh, Semper’s Reisen im Archipelago der Philippinen; Nudibranchiata: Theil ii. Band ii. (1870–78), Band iii. (1880–1892).
W. G. Binney, Terrestrial Air-breathing Mollusks of the United States: Bull. Mus. C. Z. Harv. iv. (1878), 450 pp.
„ On the Jaw and Lingual Membrane of North American Terrestrial Pulmonata: Proc. Ac. Nat. Sc. Philad. (1875), pp. 140–243.
J. T. Cunningham, The renal organs (Nephridia) of Patella: Quart. Journ. Micr. Sc. xxiii. (1883), pp. 369–375.
„ „ Note on the structure and relations of the kidney in Aplysia: Mitth. Zool. Stat. Neap. iv. (1883), pp. 420–428.
R. von Erlanger, On the paired Nephridia of Prosobranchs, etc.: Quart. Journ. Micr. Sc. xxxiii. (1892), pp. 587–623.
H. Fischer, Recherches sur la Morphologie du Foie des Gastéropodes: Bull. Scient. France Belg. xxiv. (1892), pp. 260–346.