172 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. V. 



in head ; origin of spinous dorsal midway between base of caudal and 

 nostril; pectoral ij/2 in head; ventral 2$; anal fin moderate, its base 

 i in the head; lateral line represented by a few partly developed 

 pores on fifth row of scales; gill rakers long and slender, 14 on first 

 arch; vertebrae i8-f 18 =36. 



Color silvery ; a dark lateral band, not prominent in pectoral region ; 

 scales edged with dark dots; snout, top of head, and upper part of eye 

 dusky; dorsal and caudal dusky. Length about 2^ inches. 



157. Chirostoma barton! Jordan & Evermann. 



Chirostoma humboldtianum Jordan, Proc. U. S. Nat. Mus., 1879, 



299 (not of C. & V.) ; Rio Lerma, near Guanajuato. 

 Chirostoma bartoni Jordan & Evermann, Bull. 47, U. S. Nat. Mus., 

 1896, 793; Rio Lerma, near Guanajuato: Evermann & Golds- 

 borough, Bull. U. S. Fish Comm., 1902, 152; Rio Lerma, near 

 Lerma, Mexico: Meek, Field Col. Mus. Pub. 65, 1902, 112; 

 Lerma. 



Basin of the Rio Lerma. (Lerma.) 



Head 4; depth $% to 6; D. iv-io; A. i, 13 to 15; scales 11-41. 

 Body elongate, moderately compressed, the back rounded; snout 

 pointed, 3f in head; mouth moderate, oblique, the lower jaw slightly 

 projecting; the mandible 2-^ in the head; maxillary 3^; diameter of 

 eye 4 in head ; origin of dorsal fin slightly nearer tip of snout than base 

 of caudal; pectorals if in head; ventrals 2; base of anal if; scales 

 cycloid or occasionally crenate, a few on nape reduced in size; gill 

 rakers slender, 21 on first gill arch. 



Color silvery, with scattered punctulations ; a narrow dark lateral 

 band. Length about 4 inches. 



A few specimens were taken at the fish hatchery near Lerma. 

 This species was first described from specimens taken in the Rio Lerma 

 near Guanajuato. 



158. Chirostoma attenuatum Meek. 



Chirostoma attenuatum Meek, Field Col. Mus. Pub. 65, 1902, 112; 

 Patzcuaro. 



Basin of the Rio Lerma. 



Head 4^; depth $}4; D- V-Q; A. 13; scales 11-42. Body rather 

 slender, not much compressed; lower jaw slightly the longer; mouth 

 small, oblique; maxillary reaching vertical from front of orbit; teeth 

 very small, numerous in both jaws, those in the upper jaw mostly in 

 two series, in a band in lower jaw; snout pointed, 3^ m the head; 

 mandible 3 ; interorbital space 3 ; origin of spinous dorsal over middle 

 of ventrals and nearer tip of snout than base of caudal by a distance 



