NEW MEXICO: KU 4219 (50), Colfax Co., Cimarron Cr. at Springer, 1958; KU 4235 (19), Mora Co., Sapello Cr. near Sapello, 1958; KU 4245 (157), Bernalillo Co., Rio Grande 12 mi. S Bernalillo, 1958; KU 4255 (22), Rio Arriba Co., Rio Grande at Velarde, 1958; KU 4266 (53), Sandoval Co., Rio Grande 2 mi. N Cochiti Pueblo, Marcelino Baca bridge, 1958; KU 4269 (91), San Miguel Co., Pecos R., 3 mi. S Pecos, 1958; KU 4274 (25), Sandoval Co., Jemez R. at Jemez Canyon Dam, 1958; KU 4294 (113), Guadalupe Co., Pecos R. 3 mi. N. Dilia, 1958; UMMZ 94897 (146), Pecos R. at San Tuan, 1926; UMMZ 94898 (1), Pecos R. at San Juan, 1926; UMMZ 118209 (68), Sapello Cr. at Sapello, 1937; UMMZ 133131 (7), Pecos R. 0.5 mi. N Santa Rosa, 1940; UMMZ 133136 (1), Rio Grande at Albuquerque, 1940. OKLAHOMA: KU 2329 (1), Cleveland Co.-McClain Co. line, S. Canadian R., 1952; UOMZ 26355 (10), Cimarron Co., Cimarron R. 2 mi. N. Kenton, 1957; UOMZ 5917 (2), Cleveland Co., S. Canadian R. S Norman, 1925. TEXAS: KU 3409 (18), Hemphill Co., Canadian R. at town of Canadian, 1955. WYOMING: WU 2084 (4), Platte Co., N. Platte R. at Glendo, 1956; WU 2095 (3), Converse Co., N. Platte R. at Douglas, 1956; UMMZ 104064 (58), N. Platte R. below Guernsey Dam, 1937; * UMMZ 114642 (7), drainage ditch in Wind R. drainage, 1936; * UMMZ 114644 (20), drainage ditch at Riverton, 1936; * UMMZ 127518 (63), Weston Co., Beaver Cr., 1934; * UMMZ 127681 (20), Big Horn Co., Big Horn R. tributary, 1939; * UMMZ 136488 (9), Crook Co., Belle Fourche R. 15 mi. N Devil's Tower, 1941; * WU 2122 and two uncatalogued series at WU (13), Belle Fourche R., no precise locality or date; UMMZ 159969 (14), Natrona Co., N. Platte R. 2 mi. E Casper, 1950. INTRASPECIFIC VARIATION Two subspecies of _H. gracilis_ are recognized by us: one northern and eastern, characteristically inhabiting large rivers (_H. g. gracilis_), and one southern and western, characteristically inhabiting small streams (_H. g. gulonella_). Other scientific names that have been applied to this fish in the past are listed in the synonymy.