58 PERCESOCES. 
III. Length of head 3 to 34 in the length of the fish. Lower jaw projecting, 4 or a little 
more than 4 the length of head. Anal with I 18-24 rays. 20 to 23 gill-rakers on the 
lower part of the anterior arch. 
A. Teeth small or moderate, close-set ; maxillary exposed distally. 
1. Lower jaw moderately projecting, } the length of head; pectoral 3 to % the length of 
head, extending nearly to above the middle of ventrals. 
50 to 60 scales in a longitudinal series . . . . . . . . . . . « | LD. luewus. 
60 to 75 scales in a longitudinal series . 2. . 2. 1. 1 ee ee 12, dizi. 
2. Lower jaw strongly projecting, a little more than } the length of 
head ; pectoral 2. to ? the length of head, extending a little 
beyond the middle of ventrals . . . . . . . + « « « . 18. ocotlane. 
B. Teeth strong, set rather far apart, in two series; edge of maxillary 
exposed for nearly its whole length . . . . . . . . 2). . 14 sphyrena. 
1. Chirostoma bartoni. (Tab. X. fig. 2.) 
Chirostoma bartoni, Jord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1896, p. 793°; Meek, Publ. 
Columbian Mus., Zool. v. 1904, p. 172’. 
Chirostoma attenuatum, Meek, 1. c. fig. 55°. 
Chirostoma zirahuen, Meek, t. c. p. 174, fig. 57 *. 
Depth of body 5 to 6 in the length, length of head 43 to 44. Snout as long as eye, the diameter of which 
is 34 in the length of head and a little less than the interorbital width. Teeth small; jaws equal 
anteriorly or the lower.very slightly projecting ; maxillary not or but very slightly exposed distally, not 
extending to below the eye. 17 or 18 gill-rakers on the lower part of anterior arch. Scales mostly 
with entire edges, 45 to 57 in a longitudinal series. Dorsal IV-V, I 8-10; spinous dorsal well in 
advance of anal, its origin usually nearer to tip of snout than to base of caudal. Anal I 12-15. 
Pectoral $ to 4 the length of head, extending to above base or anterior part of ventrals. Caudal forked. 
Caudal peduncle 3 to 4 as long as deep. 
Hab. Mexico, Rio Lerma System : 
Guanajuato !; Lake Patzcuaro?; Lake Zirahuen*; Lerma”. 
Here described from several specimens, measuring up to 100 mm. in total length. 
2. Chirostoma patzcuaro. (Tab. X. fig. 1.) 
Chirostoma patzcuaro, Meek, Publ. Columbian Mus., Zool. v. 1904, p. 174, fig. 56°. 
Depth of body 54 in the length, length of head 47. Snout as long as eye, the diameter of which is 32 in the 
length of head and nearly equal to the interorbital width. Teeth small; lower jaw very slightly 
projecting; maxillary very slightly exposed distally, not extending to below the eye. 20 gill-rakers on 
the lower part of the anterior arch. Scales mostly with entire edges, 45 in a longitudinal series. 
Dorsal V, I 10; spinous dorsal in advance of anal, its origin slightly nearer to tip of snout than to base 
of caudal. Anal I 15. Pectoral ? the length of head, extending a little beyond the base of ventrals. 
Caudal forked. Caudal peduncle 2} as long as deep. 
Hab. Mexico, Rio Lerma System: 
Lake Patzcuaro !. 
Here described from a single specimen from Lake Patzcuaro (Meek), measuring 
