BULLETIN FLORIDA STATE MUSEUM


gium, and this stock may have given rise, at least in part, to the present
population in the Canadian maritime provinces.
 With the openings of the Chicago and later the Maumee outlet
into glacial lakes Chicago and Maumee, N. chrysocephalus also
reached the Great Lakes drainage, there to live sympatrically with
Notropis cornutus, possibly for the first time since the stocks separated
in the Pliocene. Apparently chrysocephalus did not enter the Lake
Ontario drainage till well after cornutus. By this time the Horse-
heads connection was broken, which prevented chrysocephalus reach-
ing the Atlantic coast via the upper Susquehanna.
 The general warming of streams in North America since the re-
treat of the Wisconsin ice sheet, and particularly with man's activities
during the past century or so, has wrought significant changes in the
relative distributions of N. cornutus and N. chrysocephalus which are
still continuing. In the Ohio Valley at the height of the Wisconsin
advance, cornutus was apparently the dominant, if not the sole repre-
sentative of the Luxilus complex above roughly the mouth of the Wa-
bash River. As stream conditions changed chrysocephalus invaded
this area, and the resulting competition virtually eliminated cornutus
from the lower Ohio Valley, though isolated relict populations re-
main in the lower Kanawha River system in southern West Virginia
and in the White River system in southern Indiana. The gradual re-
placement of cornutus by chrysocephalus in eastern Ohio during the
past 35 years has been well documented by Trautman (1957: 357).

GENERIC AND SUBGENERIC NOMENCLATURAL HISTORY

Luxilus Rafinesque, 1820a: 47-48 (original description of genus and subgenus;
 type species, Luxilus chrysocephalus Rafinesque, by subsequent designation
 of Jordan and Gilbert, 1877). Girard, 1856:202-203 (name mistakenly
 allied with Notemigonus). Jordan, 1876a: 94 (Luxilus chrysocephalus syn-
 onymized with Luxilus cornutus). Jordan, 1876b: 286-287 (Hypsilepis syn-
 onymized with Luxilus). Jordan and Copeland, 1876: 134, 153 (type species
 said to be Luxilus cornutus (Mitchill), but that species was not among those
 included in Luxilus by Rafinesque; Hypsilepis a synonym). Jordan, 1877: 12,
 28-31 (Luxilus chrysocephalus a synonym of Luxilus cornutus; review of Rafin-
 esque's species; type species, Luxilus cornutus). Jordan and Gilbert, 1877: 86
 (type species, Luxilus chrysocephalus Rafinesque). Jordan, 1882: 852-854
 (Luxilus divided into three subgenera: Luxilus, Coccotis, and Alburnops).
 Jordan, 1885: 814 (subgenus of Notropis). Jordan, 1929: 82 (Luxilus restored
 to generic status).
Hypsolepis Agassiz, 1854:359 (original description of genus Hypsolepis; type
 species, by original designation, Leuciscus cornutus; name attributed to


Vol. 8