Jordan and Evermann . Fishes of North A m erica . 



1157 (d). (HIROST03I4 DIAZI. Jordan & Siiyder. 



Head 3; depth 5; depth of caudal peduncle 3} in head; eye 5J; snout 

 2|; interorbital space H; height of spiuous dorsal 4* ; soft dorsal 24; aim 1 

 2*; length of pectoral If; ventral 3; caudal 1=; D. V-ll; A. 20; P. i:, : 

 scales 69-20, 22 between dorsals. Body long, deeper and more com- 

 pressed than that of C. humboldtianum; head large, its dorsal contour 

 straight from tip of snout to occiput; viewed from above, the head is 

 much compressed, the upper jaw is sharply pointed and included l>y tin- 

 lower; interorbital space slightly convex; eye nearer tip of snout than to 

 edge of opercle by a distance equal to diameter of pupil; preorbital area a 

 little wider than diameter of orbit; mouth oblique, its cleft extending to 

 a horizontal from lower edge of orbit; lips thickened posteriorly, the 

 lower forming a fold across the upper at angle of mouth; lower jaw pro- 

 jecting, the teeth just passing the edge of the upper; maxillary extending 

 to a vertical from anterior edge of orbit, its distal end angular; teeth 

 large anteriorly, growing gradually smaller posteriorly, canine-like, sharp, 

 projecting backward, not arranged in definite rows, none on vomer or 

 palatines; vertebra? 44. Scales creuate, larger in region of lateral color 

 band, growing smaller dorsally and ventrally, abruptly smaller and closely 

 crowded together in a region anterior to the pectoral fin, extending from 

 the isthmus to the occiput, also between the dorsal fins and along bases of 

 dorsals, anal and caudal; inter-radial membranes of the latter with scales 

 extending its length ; head with scales except on jaws, upper part of 

 snout, and on preorbital area; two anterior spines of dorsal longest, others 

 a little shorter; first dorsal ray longest, others gradually shorter; anal 

 similar to soft dorsal in shape, except that its base is much longer; inser- 

 tion of anal on a perpendicular passing halfway between dorsals ; caudal 

 deeply forked, the lobes pointed; pectoral sharp, extending past base of 

 ventrals a distance equal to diameter of orbit; edge of pectoral, when 

 extended, straight. Body, during life, translucent; in alcohol, greenish 

 olive; a silvery lateral baud, in which the silver is not underlaid with 

 black pigment, extending from axil to base of caudal; dorsal scales nar- 

 rowly edged with dusky; upper part of eye dark. Jalisco, Mexico. 



Our specimens are all from the market at Guadalajara. The gill-arches 

 and viscera had been removed. The flesh is somewhat shrunken, which 

 probably causes the teeth to appear more prominent than in life. 



Chirostoma dia:i may be easily distinguished from the other known 

 species of the genus by the small scales crowded closely together between 

 the dorsal fins. (Jordan &, Snyder.) 



Known only from the market at Guadalajara, Jalisco, Mexico. (Type, 

 No. 6157, L. S. Jr. Univ. Mus. Coll. J. O. Snyder.) 



(Named for Porfirio Diaz, the honored President of the Republic of 

 Mexico, in recognition of his interest in the progress of science.) 



Chirostoma diazi, JORDAN &, SNYDER, Bull. U. S. Fish Com. 1899 (1900), 137, Guadalajara, 

 Mexico. 



