FALCULA.—NOTROPIS. 155 
eye, the diameter of which is 5 to 6 in the length of head ; interorbital width 34 to 3% in the length of 
head. Mouth terminal, oblique. Dorsal 10, with 7 branched rays 5 origin equidistant from tip of snout 
and base of caudal or a little nearer the former; longest ray & to 2 the length of head. Anal 10. 
Ventrals inserted below or in advance of the origin of dorsal. 45 to 50 scales in a longitudinal series, 
8 ina transverse series from origin of dorsal to lateral line, 4 or 5 between lateral line and base of 
ventral. Silvery, back darker ; fins pale. 
Hab. Mexico, Rio Lerma System: 
Lake Chapala}? (Buller); Ojo de Agua, Michoacan (Mexico Mus.). 
Here described from four specimens, 130 to 190 mm. in total length. 
12. NOTROPIS, Rafin., 1818. 
Notropis, Jord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1896, p. 254. 
This genus differs from Leuciseus in the smaller number of pharyngeal teeth, in 
one or two series, 4, 0-2—0-2, 4. 
The scales are large (30 to 60 in a longitudinal series), and the ventral fins are 
8-rayed. 
A large number of species of small fishes from the United States east of the Rocky 
Mountains and from Mexico. 
Synopsis of the Mexican Species. 
I. Mouth subterminal, the lower jaw included. 
35 to 39 scales in a longitudinal series . 1. boucardi. 
42 scales in a longitudinal series . 2. orca. 
48 to 54 scales in a longitudinal series . . . . - + + = © 3. nazas. 
54 to 60 scales in a longitudinal series 4. sallei. 
II. Mouth terminal, oblique, with the jaws equal anteriorly. 
A. 82 to 40 scales in a longitudinal series. 
1. Lateral line complete or absent on a few scales posteriorly. 
5. chihuahua. 
a. Caudal peduncle 24 as long asdeep. . «. - - + + + + + 
b. Caudal peduncle not more than twice as long as deep. 
a. Diameter of eye 24 (young) to 34 (adult) in the length of head ; 
32 to 36 scales in a longitudinal series . . 6. macrostomus. 
8. Diameter of eye 34 to 5 in the length of head ; 34 to 40 scales 
in a longitudinal series. 
Males with several dark cross-bars ; anal fin of 8 or 9 rays ee 
Males with a dark vertical bar behind the head ; anal fin of 9 or 10 rays; 
length of head 32 to 4 in the length of the fish . . 
Males with a dark vertical bar behind the head; anal fin of 10 to 12 rays ; 
length of head 4: to 43 in the length of the fish. . - - «© s+ 2 « = 
9. Lateral line incomplete, not continued beyond the ventral fins. 
7. ornatus. 
8. /utrensis. 
9. garmant. 
. 10. santamarie. 
. Ll. calientis. 
X 2 
38 scales in a longitudinal series . 
32 to 35 scales in a longitudinal series 
