Mention is made of fish only twice in the entire log. We doubt that Muddy Creek or the East Laramie River is the type locality of _P. gulonellus_, because the flathead chub has not since been found in either of these streams. The most likely collection site for _P. gulonellus_ is the North Platte River near the mouth of Sage Creek, in what is now Carbon County, Wyoming, where the expedition was camped for three days. This species is known to occur in the North Platte River, and since the type locality is reported as "near Bridger's Pass" this is the probable location. _Range_ (Plate 21).--Upper mainstream and tributaries of Rio Grande, Pecos, Arkansas and North Platte Rivers; isolated populations in tributaries of the upper Missouri River. _Specimens examined._--Below are listed museum numbers, number of specimens (in parentheses), localities and year of collection. Series marked by asterisks (*) are intergrades tending toward _H. g. gulonella_. Literature reports are cited in the synonymy. COLORADO: KU 4742 (162), Bent Co., Purgatoire R. at Las Animas, 1959; KU 4748 (105), Pueblo Co., Arkansas R. at west edge of Pueblo, 1959; KU 4758 (50), Fremont Co., Arkansas R. at Florence, 1959; KU 4769 (64), Fremont Co., Beaver Cr., 1959. KANSAS: KU 2648 (2), Finney Co., Arkansas R., 1958; KU 2858 (13), Finney Co., Arkansas R. at Garden City, 1951; KU 3964 (12), Kearney Co., Arkansas R., 1958; * KU 4041 (2), Cheyenne Co., Republican R., 1958; KU 4732 (30), Hamilton Co., Arkansas R. at Kendall, 1959; * KU 4868 (1), Kansas-Nebraska line, Republican R. 1.5 mi. S. Hardy, 1959. MONTANA: * MSC 1960 (8), Powder River Co., E. Fork of Powder R., 1957; MSC 2010 (64), Dawson Co., Redwater R., 1957. NEBRASKA: * KU 2140 (2), Dawson Co., Platte R., at Gothenburg, 1931; * KU 4863 (20), Furnas Co., Republican R. at Cambridge, 1959; * UM (field no. 59-49) (74), Scotts Bluff Co., North Platte R. at Morrill, 1959; * UMMZ 133918 (17), Dixon Co., Logan Cr., 1939; * UMMZ 134813 (31), North Platte R., Neb.-Wyo. line, 1941; * UMMZ 135084 (14), Harlan Co., Beaver Cr. 0.25 mi. S Stamford, 1940; * UMMZ 135200 (41), Scotts Bluff Co., North Platte R. 1 mi. SE Henry, 1940; * UMMZ 135280 (59), Cherry Co., Niobrara R. 3 mi. SE Valentine, 1940; * UMMZ 135700 (25), Buffalo Co., South Loup R. 8 mi. N Miller, 1941; * UMMZ 135778 (54), Thurston Co., Logan Cr. 2.5 mi. W Pender, 1941; * UMMZ 135786 (25), Dixon Co., Logan Cr. 0.5 mi. NW Wakefield, 1941.