154 OSTARIOPHYSI. 
Hab. Colorado and Gila Rivers!23, headwaters of the Rio Yaqui, at Mifiaca in 
Chihuahua ‘. 
The species attains a length of 300 mm. or more. Some of the distinctive characters 
assigned to G. minace by Dr. Meek are evidently due to the small size of the specimen 
described. 
2. Leuciscus nigrescens. 
Gila pulchella (non Leuciscus pulchellus, Storer), Baird & Girard, Proc. Ac. Philad. 1854, p. 29°. 
Tigoma pulchella, Girard, Proc. Ac. Philad. 1856, p. 206°, and U.S. & Mex. Bound. Surv., Fish. 
p. 62, t. 84. figs. 5-8 (1859) *. 
Tigoma nigrescens, Girard, t. c. p. 207 *, and t.c. p. 64, t. 32. figs. 1-4’, 
Tigoma pulchra, Girard, |. c.°, and t. c. p. 65”. 
Tigoma conspersa, Garm. Bull. Mus. Comp. Zool. viii. 1881, p. 91°. 
Cheonda modesta, Garm. t.c. p. 92°. 
Cheonda nigrescens, Garm. |. c.”°. 
Leuciscus nigrescens, Jord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1896, p. 233°'; Meek, Publ. 
Columbian Mus., Zool. v. 1904, p. 557’. 
Depth of body 33 to 43 in the length, length of head 34 to 4. Snout longer than eye, the diameter of which 
is 43 (young) to 54 in the length of head ; interorbital width 3 in the length of head. Mouth terminal, 
oblique. Dorsal 10, with 8 branched rays; origin above the insertion of the innermost ray of the 
ventral. Anal 9. 60 to 75 scales in a longitudinal series, 15 to 18 in a transverse series from origin 
of dorsal to lateral line, 8 to 10 between lateral line and base of ventral. Lateral line complete. 
Silvery, back darker ; a dark lateral stripe ending in a caudal spot present in the young. 
Hab. Mexico, Chihuahua, Coahuila, and Durango: 
Rio Grande !!; Rio Casas Grandes (MJeek)1234512. Rio Santa Maria !2, Rio 
Carmen !2 and Rio Conchos (Woolman)®7¥ in Chihuahua; Parras!® and 
Saltillo ® in Coahuila; Rio Nazas*™ and Durango (Meek) }° in Durango. 
Here described from several specimens measuring up to 150 mm. in total length. 
11. FALCULA, Jord. & Snyd., 1900. 
Foicula, Jord. & Snyd. Bull. U.S. Fish. Comm. xix. 1899, p. 124 (1900). 
Although the single species of this genus does not appear to be specially closely 
related to the small fishes which are comprised in Notropis, it is difficult to find 
characters by which to separate it from them generically. Until a study of the 
anatomy makes its relationships clear, the external character of the larger number of 
rays (10 instead of 8) in the ventral fins may be used. 
1. Falcula chapale. 
Falcula chapale, Jord. & Snyd. Bull. U.S. Fish. Comm. xix. 1899, p. 125, fig. (1900) *; Meek, 
Publ. Columbian Mus., Zool. v. 1904, p. 58, fig. 12°. 
Depth of body nearly equal to the length of head, which is 4 in the length of the fish. Snout longer than 
