3164 Bulletin 47, United States National Museum. 



ventrals; head long, pointed, its dorsal contour straight from tip of 

 nout to a point a little posterior to the eye, where it curves upward; 

 interorbital space flat; eye high up, nearer tip of snout than edge of 

 opercle by a distance about equal to diameter of pupil; width of pre- 

 orbital space equal to diameter of pupil; mouth oblique, the cleft extend- 

 ing downward to a point opposite lower edge of pupil; lips growing more 

 fleshy posteriorly, the lower forming a fold across the upper at their junc- 

 tion; distal end of maxillary angular, extending almost to a vertical from 

 anterior edge of orbit; lower jaw very long, projecting beyond upper a 

 distance equal to diameter of pupil; viewed from above, both jaws are a 

 little more pointed than are those of C. estor or of C. humloldtianum. 

 Teeth on jaws in bands, minute, projecting backward; no teeth on vomer 

 or palatines; gill-rakers slender, close together, length of longest equal to 

 diameter of pupil; vertebrae 44. A rather indefinite lateral line extend- 

 ing along body, 10 scales below the first dorsal, the pores absent on many 

 of the scales; scales crenate, growing smaller dorsally, larger veutrally, 

 those on posterior part of occiput, on nape, on region anterior to pec- 

 toralsabove and below, and on base of caudal, very small and crowded 

 together, those in the region of dorsals not reduced in size or crowded 

 except at insertion of fins, where there are 4 very small ones; cheek 

 with 5 rows; lower jaw and upper part of snout naked; basal half of inter- 

 radial membranes of caudal with minute scales; firsts spines of dorsal 

 highest, extending when depressed within half their length of origin of 

 soft dorsal ; first dorsal ray preceded by a shorter, simple, closely attached 

 one ; other rays successively shorter than first ; edge of fin slightly con- 

 cave; anal similar to soft dorsal in shape, its basis If times as long as that 

 of soft dorsal ; attachment of first ray under a point half way between 

 insertions of dorsals; caudal deeply forked, the lobes equal; pectoral 

 pointed when depressed, upper rays longest, extending to a vertical half 

 way between insertions of first dorsal and ventrals. Body, during life, 

 almost translucent, with a bluish tinge of color; in alcohol, the color is a 

 light olive yellow; a silvery lateral band extending from axil to base of 

 caudal, the band wider and brighter in color between dorsal and anal, 

 growing narrow on caudal peduncle and then widening again at its pos- 

 terior end. Head and body above, and the lower jaw, dusky; upper part 

 of eye dark ; edge of scales above lateral baud with small black dots ; 

 caudal somewhat dusky on its basal third ; other fins with little or no dark 

 color. 



Chirostoma ocotlane is easily distinguished from all other known species 

 of the genus by its excessively long lower jaw. Except the jaw and some- 

 what larger eye it resembles C. estor in general appearance. Laguna de 

 Chapala, Mexico. (Jordan & Snyder.) 



Known only from Laguna de Chapala, near Ocotlan, Mexico. (Type, 

 No. 6160, L. S. Jr. Univ. Mus. Coll. J. O. Snyder. ) 



Chirostoma ocotlane, JORDAN <fc SNYDER, Bull. U. S. Fish Com. 1899 (1900), 141, Laguna 

 de Chapala, near Ocotlan, Mexico. 



