62 PERCESOCES. 
10. Chirostoma promelas. 
Chirostoma promelas, Jord. & Snyd. Bull. U.S. Fish. Comm. xix. 1899, p. 136, fig. 14°; Jord. & 
Everm. Bull. U.S. Nat. Mus. xlvii. 1900, p. 83160°; Meek, Publ. Columbian Mus., Zool. v. 
1904, p. 177°. 
Allied to C. luctus, but with the lower jaw shorter than the upper. DorsalIV,I 11. Anal 119-20. Scales 
with crenate edges, 53 to 56 in a longitudinal series. 
Hab. Mexico, Rio Lerma System : 
Lake Chapala ? 8, 
11. Chirostoma lucius. 
Chirostoma lucius (part.), Bouleng. Ann. Mag. Nat. Hist. (7) v. 1900, p. 54°. 
Chirostoma crystallinum, Jord. & Snyd. Bull. U.S. Fish. Comm. xix. 1899, p. 139, figs. 16 & 17 
(1900) *; Jord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1900, p. 3162’. 
Chirostoma lucius, Meek, Publ. Columbian Mus., Zool. v. 1904, p. 178, fig. 60°. 
Depth of body 4 in the length, length of head 34. Snout 12 as long as eye, the diameter of which is 53 in 
the length of the head; interorbital width 4 in the length of head. Teeth rather small; lower jaw 
projecting, 3 the length of head; maxillary exposed distally, extending to the vertical from the anterior 
margin of eye; 20 gill-rakers on the lower part of the anterior arch. Scales with crenate edges, 
52 in a longitudinal series. Dorsal VI, I 11; spinous dorsal in advance of the anal, its origin nearer to 
base of caudal than to tip of snout. Anal I 20. Pectoral 2 the length of head, extending nearly 
to above the middle of ventrals. Caudal forked. Caudal peduncle twice as long as deep. 
Hab. Mexico, Rio Lerma System : 
Guadalajara?; Lake Chapala! ? (Buller). 
Here described from the type of the species, measuring 200 mm. in total length. 
Jordan and Snyder give the following numbers for C. crystallinum:—Dorsal IV-V, 
IT 11-13. Anal 118-24. 56 to 60 scales in a longitudinal series. 
12, Chirostoma diazi. 
Chirostoma diazi, Jord. & Snyd. Bull. U.S. Fish. Comm. xix. 1899, p. 187, fig. 15 (1900) '; Jord. & 
Everm. Bull. U.S. Nat. Mus. xlvii. 1900, p. 3161’. 
Chirostoma sphyrena, Meck, Publ. Columbian Mus., Zool. v. 1904, p. 177, fig. 59°. 
Closely allied to the preceding species, but with smaller scales (60 to 75 in a longitudinal series); dorsal scales 
very small and irregular, 21 to 27 in a series between the two dorsal fins. Dorsal IV-V, I 11-12. 
Anal I 20-22. 
Hab. Mexico, Rio Lerma System: 
Lake Chapala }. 
13. Chirostoma ocotlane. (Tab. IX. fig. 1.) 
Chirostoma lucius (part.), Bouleng. Ann. Mag. Nat. Hist. (7) v. 1900, p. 54°, 
Chirostoma ocotlane, Jord. & Snyd. Bull. U.S. Fish. Comm. xix. 1899, p. 140, fig. 18 (1901) *; 
Jord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1900, p. 3163° ; Meek, Publ. Columbian Mus., 
Zool. v. 1904, p. 180, fig. 62%. 
