EVARRA.—XYSTROSUS. 16] 
1. Evarra eigenmanni. 
Evarra eigenmanni, Woolman, Bull. U.S. Fish. Comm. 1894, p. 64'; Jord. & Everm. Bull. U.S. 
Nat. Mus. xlvii. 1896, p. 3047; Meek, Publ. Columbian Mus., Zool. v. 1904, p. 77, 
fig. 23°. 
Depth of body 53 in the length, length of head 43. Diameter of eye 42 in the length of head. Snout obtuse ; 
mouth small. Dorsal 9, with 7 branched rays; origin nearer to base of caudal than to tip of snout. 
Anal 8. Ventrals inserted in advance of the origin of dorsal. 85 scales in a longitudinal series, 15 in 
a transverse series from origin of dorsal to lateral line, 9 between lateral line and base of ventral. 
Lateral line complete. Silvery, back darker; an indistinct lateral stripe ending in a small caudal spot. 
Hab. Valley of Mexico: 
City of Mexico! ? (Woolman); Tlahuac °. 
Here described from the type, 60 mm. in total length. 
2, Evarra tlahuacensis. 
Evarra tlahuacensis, Meek, Publ. Columbian Mus., Zool. v. 1904, p. 78, fig. 24°. 
Differs from the preceding in the smaller scales (95 in a longitudinal series) and the longer anal fin (of 
14 rays). 
Hab. Valley of Mexico, Tlahuac!. 
14. PHENACOBIUS, Cope, 1867. 
Phenacobius, Jord. & Everm. Bull. U.S. Nat. Mus. xlvii, 1896, p. 302. 
Body elongate, little compressed. Mouth protractile, inferior ; lower lip produced into a fleshy lobe on each 
side; no barbels. Pharyngeal teeth compressed, hooked, in a single series, 4—4. Scales small or 
moderate (40 to 60 in a longitudinal series); lateral line complete. Dorsal and anal fins short. 
This genus comprises five species, small fishes of the Eastern United States and the 
Mississippi System, one extending south to the Rio Grande. 
1. Phenacobius scopifer, Cope, 1870. 
Phenacobius scopifer, Jord. & Everm, Bull. U.S. Nat. Mus. xlvii. 1896, p. 303'; Meek, Publ. 
Columbian Mus., Zool. v. 1904, p. 76°. 
Hab. Illinois to the Rio Grande ! ?. 
15. XYSTROSUS, Jord. & Snyd., 1900. 
Xystrosus, Jord. & Snyd. Bull. U.S. Fish. Comm. xix. 1899, p. 123 (1900). 
This genus appears to be nearest to Falcula, but is at once distinguished by the numerous very long and 
slender gill-rakers. 
A single species from Lake Chapala. 
1. Xystrosus popoche. . 
Xystrosus popoche, Jord. & Snyd. Bull. U.S. Fish. Comm. xix. 1899, p. 123, fig. (1900) *; Meek, 
Publ. Columbian Mus., Zool, v. 1904, p. 48, fig. 7’. 
Depth of body 4 to 43 in the length, length of head 33. Mouth rather large, terminal, oblique; gill-rakers 
Y 
BIOL, CENTR.-AMER., Pisces, February 1908. 
