The genus Gyrodactylu3 von Nordmani, 1832, included all described species of Dactylogyrus prior to 1850 when Diesin;g established the latter taxonomic category. Validity of this separation was confirmed by Bychowsky when he erected the subfamily Dactylogyrinae in 1933(a). The first mention of Dactylogyrus in North America was that of Hess (1928) who re ported undetermined species from various hosts. His observations were only partially correct since sunfish and smalland large-mouth basses which Dactylogyrinae normally do not infest, were included with goldfish, carp, and "other fishes" as harboring these species. Hess (1930) more correctly referred to goldfish and carp since Dactylogyrus anchoratus (Dujardin, 1845) was recorded from Europe for the former host and D. extensus, the first valid species record for North America, was described from the latter host by Mtieller and Van Cleave in 1932. North American work on dactylogyrids was resumed when Mueller (1936) reportzd D. anchoratus (Dujardin, 1845) from the gills of Carassius auratus. Mueller (1936) observed the preponderance of Dactylogyrus species in Europe as compared to North America and concluded this genus to be predominantly European. Subsequent investigation proved this conclusion false as later admitted by Mueller (1938). Mizelle (1937) described Dactylogyrus bychowskyi, D. bifurcatus and D. simplexus nov. nom. frcm the blunt-nosed minnow (Hyborhynchus notatus) and added D. atromaculatus from the creek chub (Semotilus atromaculatus) in 1938. Mueller (1938) described 16 new species from various minnows and suckers (Appendix I). Thus it became increasingly clear that this genus was almost as well represented in North America as in Europe and Asia, collectively (see below). The chief reason that earlier American workers failed to discover members of this subfamily is that examinations were restricted principally to native game fishes with almost total exclusion of cyprinids which comprise the largest family of North American fresh. water fishes. In 1938 Price erected the problematical genus Neodactylogyrus on the basis of the presence of two supporting haptoral bars. Kimpel (1939) reported the description of 6 species in this generic category (Appendix I). Mizelle and Donahue (1944) described 3 species, D. banghami, D. bullosus and D. pollex from the common shiner (Notropis cornutus) and questioned the validity of the genus Neodactylogyrus. Sproston (1946) recog-nized Neodactylogyrus, Dactylogyrus and Dogielius (monotypic) as the three genera which consti-