154 OSTAEIOPHYSI. 



Hah. Colorado and Gila Rivers 1 2 s^ headwaters of the Rio Yaqui, at Minaca in 

 Chihuahua *. 



The species attains a length of 300 mm. or more. Some of the distinctive characters 

 assigned to G. minaccB by Dr. Meek are evidently due to the small size of the specimen 

 described. 



2. Leuciscus nigrescens. 



Gila pidchella (non Leuciscus pulchellus, Storer), Baird & Girard, Proc. Ac. Philad. 1854^ p. 29 '. 

 rigoma pulchella, Giravd, Proc. Ac. Pliilad. 1856, p. 206", and U.S. & Mex. Bound. Surv., Fish. 



p. 62, t. 34. figs. 5-8 (1859)1 

 Tigoma nigrescens, Girard, t. c. p. 207 ■*, and t. c. p. 64, t. 32. figs. 1-4'. 

 Tigomci pulchra, Girard, 1. 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. 1. c.'°. 

 Leuciscus nigrescens, Jord. & TLycrm. Bull. U.S. Nat. Mus. xlvii. 1896, p. 233"; Meek, Publ. 



Columbian Mus., Zool. v. 1904, p. 55 '". 



Depth of bod)' 3j to 4j in the length, length of head 3g to 4. Snout longer than eye, the diameter of which 

 is 44 (young) to 6j in the length of head ; interorbital width 3 in the length of head. Month terminal, 

 oblique. Dorsal 10, with 8 branched rays ; origin above the insertion of tlie innermost ray of the 

 ventral. Anal 9. 60 to 75 scales in a longitudinal series, 15 to IS 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 (3£eek) i 2 s 4 5 12^ j^q ganta Maria ^-, Rio 

 Carmen i- and Rio Conchos ( Woolman) ^ ^ ^" in Chihuahua ; Parras 10 and 

 Saltillo ^ in Coahuila ; Rio Nazas ^ ^^ ^nd Durango {Meek) ^^ in Durango. 



Here described from several specimens measuring up to 150 m)n. in total length. 



11. FALCULA, Jord. & Snyd., 1900. 

 Falcula, 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 chapalae. 



Falcula chapalm, Jord. & Snyd. Bull. U.S. FisL. 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 louii-er than 



