Notes on Some Nematodes from Fresh-Water Fishes

The parasitic nematodes are of conspicuous importance in the field of human disease and also in diseases of the domestic animals, and in his treatise on fish diseases, Hofer (1906), discussing the significance in fish culture of parasites and parasitic disease5, states that among them the nematodes outrank all others in number of types. Yet as fish parasites these forms are almost unknown in North America, and references to them are confined to a few brief notes, almost all of which came from the pen of the distinguished Philadelphia microscopist, anatomist, and parasitologist, Joseph Leidy, whose pioneer work published between 1850 and 1886 includes many records of great value on this group. In this little-explored field the senior author (Ward) has been making observations for many years and in collaboration with the junior author (Magath) was led recently to undertake an extended study of nematode parasites from North American fresh-water fishes which has yielded a number of new and interesting forms; these are briefly described here in advance of the appearance of the complete article in which will be given fuller data on the structure and relationships of these species. Especial thanks are due the United States Bureau of Fisheries for aid in securing material. It is interesting to note that among the eight forms described as new species, three fall within new genera and five agree sufficiently with European forms to be listed in already existing genera. Seven out of the nine forms described in this paper come within the limits of the Spiruroidea, so that this superfamily appears to hold a prominent place among parasites of fresh-water fishes