CHIROSTOMA. 59 
90 mm. in total length. Dr. Meek’s type has V, I 10 dorsal rays, I 17 anal rays, and 
48 scales in a longitudinal series. 
3. Chirostoma arge. 
Esloparsum arge, Jord. & Snyd. Bull. U.S. Fish. Comm. xix. 1899, p. 133, fig. 12 (1901) '; 
Jord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1900, p. 3158 *. 
Chirostoma arge, Meek, Publ. Columbian Mus., Zool. v. 1904, p. 171, fig. 54°. 
Depth of body 44 to 5 in the length, length of head 43 to 43. Snout as long as eye, the diameter of which 
is 34 in the length of head and nearly equal to the interorbital width. Teeth small; lower jaw very 
slightly projecting ; maxillary very slightly exposed distally, extending to the vertical from the anterior 
margin of eye. 11 or 12 gill-rakers on the lower part of the anterior arch. Scales with entire edges, 
36 to 42 in a longitudinal series. Dorsal III-IV, I 8-9; spinous dorsal in advance of anal, its origin 
nearly equidistant from tip of snout and base of caudal. Anal I 14-17. Pectoral about ? the length of 
head, extending to or a little beyond the base of ventrals. Caudal forked. Caudal peduncle 2 to 23 as 
long as deep. 
Hab. Mexico, Rio Lerma System: 
Aguas Calientes!°; Lagos °. 
Here described from several specimens, measuring up to 70 mm. in total length, 
from Aguas Calientes (Jordan) and Lagos (Meek). 
4. Chirostoma jordani. 
Chirostoma jordani, Woolman, Bull. U.S, Fish. Comm. xiv. p. 62, t. 2 (1895)*; Jord. & Everm. 
Bull. U.S. Nat. Mus. xlvii. 1896, p. 793°; Meek, Publ. Columbian Mus., Zool. v. 1904, 
p. 169, fig. 52°. 
Chirostoma mezquital, Meek, t. c. p. 170, fig. 53°. 
Depth of body 4 to 5 in the length, length of head 44 to 43. Snout shorter than eye, the diameter of which 
is 3 to 34 in the length of head; interorbital width about 3 in the length of head. Teeth small; lower 
jaw very slightly projecting; maxillary not exposed, not quite reaching the vertical from the anterior 
margin of eye. 16 gill-rakers on the lower part of anterior arch. Scales with entire edges, 38 to 42 in 
a longitudinal series. Dorsal III-IV, I 8-10; origin of spinous dorsal nearly equidistant from tip of 
snout and base of caudal; last dorsal spine inserted above the origin of anal. Anal I 16-19. Pectoral 
a little shorter than the head, extending to above the middle of ventrals. Caudal peduncle twice as 
long as deep. 
Hab. Mxxtco, Rio Mezquital and Rio Lerma Systems, Valley of Mexico : 
Durango? ; Aguas Calientes*; Lagos?; Salamanca *; Lake Chapala? *; Acam- 
baro?; Lake Cuitzeo?; Texcoco?; Chalco?; City of Mexico! 3; Yautepec °. 
Here described from specimens from Salamanca (Woolman) and Acambaro (Meek), 
measuring up to 65 mm. in total length. 
5. Chirostoma breve. (Tab. X. fig. 3.) 
Chirostoma breve, Steind. Denkschr. Ak, Wien, lxii. 1895, p. 526, t. 2. fig. 2 4 
Chirostoma labarce, Meek, Publ. Columbian Mus., Zool. v. 1904, p. 173 *, 
Depth of body 4 to 43 in the length, length of head 4 to 43. Snout as long as or a little longer than the eye, 
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