EVAREA.— XTSTEOSUS. 161 



1. Evarra eigenmanni. 



Evarra eigenmanni, Woolman, Bull. U.S. Fish. Comm. 1894, p. 64'; Jord. & Everm. Bull. U.S. 

 Nat. Mus. xlvii. 1896, p. 304=; Meek, Publ. Columbian Mus., Zool. v. 1904, p. 77, 

 fig. 23 \ 



Depth of body 5i in the length, length of head 4|. Diameter of eye 4| in the length of head. Snout obtuse ; 

 mouth small. Dorsal 9, with 7 branched rays: origin nearer to base of candal 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 i 2 ( Woolman) ; Tlahuac 3. 



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). 



Ilab. Valley of Mexico, Tlahuac 1. 



14. PHENACOBIUS, Cope, 1867. 



Phenacohius, Jord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1896, p. 302. 



Body elongate, little compiressed. Mouth protractile, inferior ; lower hp produced into a flesh}' 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 extendmg south to the Eio Grande. 



1. Phenacobius scopifer, Cope, 1870. 



Phenacohius 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 Eio Grande i 2. 



15. XYSTROSUS, Jord. & Snyd., 1900. 

 Xystrosus, Jord. & Snyd. Bull. U.S. Fish. Comm. xix. 1899, p. 123 (I'JOO). 



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. 



Xystrostis popoche, Jord. & Suyd. Bull. U.S. Fish. Comm. xix. 1899, p. 123, fig. (1900) '; Meek, 



Publ. Columbian Mus., Zool. v. 1904, p. 43, fig. 7"'. 

 Depth of body 4 to 4^ in the length, length of head oh Mouth rather large, terminal, oblique ; gill-rakcrs 



BIOL. CBNTR.-AMER., Pisces, February 1908. Y 



