FAMILY XIV. ATHERINID^;. 171 



Head 4.K; depth 5^; D. iv-io; A. 19; scales 11-40 to 42. Body 

 elongate, not much compressed; snout short, its length 3^ in head;- 

 mouth small, quite oblique; maxillary scarcely reaching vertical from 

 front of eye; jaws equal; teeth small, in one series in each jaw; eye 

 large, 3 in head; interorbital 3 in head; origin of spinous dorsal over 

 middle of ventrals, about a distance equal to diameter of eye nearer 

 tip of snout than base of caudal ; anal fin long, its base nearly one-half 

 longer than head; scales with entire edges; pectoral i^ in head; ven- 

 trals i ^3 ; a few scales at the nape reduced in size. 



Color light olivaceous, a narrow blue strip on the side; edges of 

 scales on upper half of body with black dots; very few dark dots on 

 scales on lower half, except near base of anal fin. Length about 3 

 inches. 



This species is more nearly related to the preceding than to any 

 other; it is more slender, and the spinous dorsal has a more forward 

 position. At present it is the only member of the genus in Mexico 

 known outside of the Lerma basin. A few specimens were taken 

 from the Rio Mezquital near Durango. 



156. Chirostoma arge (Jordan & Snyder). 



Eslopsarum arge Jordan & Snyder, Bull. U. S. Fish Comm., 1900, 



113, fig. 12; Rio Verde, Aguas Calientes: Jordan & Evermann, 



Bull. 47, U. S. Nat. Mus., 1900, 3158. 

 Chirostoma arge Meek, Field Col. Mus. Pub. 65 ? 1902, 112; Aguas 



Calientes; Lagos. 

 Basin of the Rio Lerma. 



FlG. 54. CHIROSTOMA ARGE (Jordan & Snyder). 

 No. 6154, Leland Stanford Jr. University. 



Head 4%; depth 4%; D. iv-8; A. 16 or 17; scales 11-38 to 41. 

 Body rather robust, deepest part just anterior to base of ventrals; 

 mouth rather large, oblique; lower jaw projecting slightly beyond the 

 upper; snout pointed, its length 3 in head; teeth large, sharp, in 

 two definite rows on each jaw, none on vomer or palatines; maxillary 

 reaching vertical from anterior margin of the orbit ; diameter of eye 2% 



