162 OSTARIOPHYSI. 
very long, slender, and numerous. 60 to 70 scales in a longitudinal series. Dorsal 9-10, with 
7 branched rays; origin equidistant from tip of snout and base of caudal and above the insertion of the 
ventrals, Anal 8-10, with 6 or 7 branched rays. Silvery, back darker ; fins plain. 
Hab. Mexico, Lake Chapala in Jalisco 1? (Buller, Meek). 
I have examined three specimens, 200 to 230 mm. in total length. 
16. STYPODON, Garm., 1881. 
Stypodon, Jord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1896, p. 220. 
Body oblong, compressed. Mouth small, protractile; no barbels. Pharyngeal teeth cylindrical, with convex 
apices, in a single series, 3—3. Scales large (85 in a longitudinal series); lateral line complete, 
decurved. Dorsal and anal fins short. 
A single species from Coahuila. 
1. Stypodon signifer. 
Stypodon signifer, Garm. Bull. Mus. Comp. Zool. viii. 1881, p. 90'; Jord. & Everm. Bull. U.S. 
Nat. Mus. xlvii. 1896, p. 2207; Meek, Publ. Columbian Mus., Zool. v. 1904, p. 51°. 
Hab. Mexico, Lake Parras in Coahuila}. 
17. PIMEPHALES, Rafin., 1820. 
Pimephales, Jord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1896, p. 216. 
Body more or less elongate, moderately compressed. Mouth small, inferior, protractile; no barbels. 
Pharyngeal teeth with oblique grinding-surface, usually not hooked, in a single series, 4—4. Scales 
moderate. Dorsal and anal fins short, the former with the first ray more or less spinous (in adult males 
covered by a thick skin) and separated from the second by a membrane. Intestine elongate. 
Three or four species from the United States and Northern Mexico. 
1. Pimephales confertus. 
Hyborhynchus confertus, Girard, Proc. Ac. Philad. 1856, p. 179 - 
Pimephales promelas confertus, Jord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1896, p. 217 *. 
Pimelocephales confertus, Meek, Publ. Columbian Mus., Zool. v. 1904, p. 50°. 
Depth of body 32 to 33 in the length, length of head 33 to 4. Snout obtuse; diameter of eye 34 to 32 in the 
length of head. Dorsal 10, with 8 branched rays. Anal 8. 50 to 55 scales in a longitudinal series, 
8 between lateral line and base of ventral. A dark lateral stripe; males dark with pale vertical bars. 
Hab. South-western Texas and Northern Mexico: 
Rio Pecos! and Brownsville 2 in Texas; Rio Casas Grandes *, Rio Santa Maria °, 
Rio Conchos ? (Meek) and Mifiaca® in Chihuahua. 
Here described from six specimens, measuring up to 60 mm. in total length. 
18. COCHLOGNATHUS, Baird & Girard, 1854. 
Cochlognathus, Jord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1896, p. 251. 
Differs from Pimephales especially in the structure of the jaws, each of which is provided with a hard cutting- 
