172 | OSTARIOPHYSI. 
Tetragonopterus fulgens, Bocourt, 1. c."°; Vaill. & Pellegr. 1. ¢."’. 
Tetragonopterus streetsit, Cope, Proc. Ac, Philad. 1871, p. 217”. 
Astyanax mexicanus, Kigenmann & Ogle, Bull. U.S. Nat. Mus. xxxiii. 1907, p. 25. 
Depth of body 2? to 34 in the length, length of head 32 to 42. Snout obtuse, nearly as long as or shorter 
than eye, the diameter of which is 2? (young) to 33 in the length of head; interorbita] width 22 to 24 
in the length of head. Maxillary extending about to the vertical from anterior edge of pupil, or 
sometimes nearly to below middle of eye; maxillary teeth 0 to 5. 10 to 14 gill-rakers on the lower 
part of anterior arch. 33 to 39 scales in a longitudinal series, 6 to 8 in a transverse series from 
dorsal fin to lateral line, 44 to 7 between lateral line and root of ventral fin. Dorsal 10-12; origin 
above or a little behind the base of last ray of ventral; longest ray $ to 2 the length of head; free 
edge of the fin straight or slightly convex. Anal 20-27, with 3 or 4 simple and 17 to 24 branched 
rays, free edge usually slightly emarginate. Pectoral 2 to 3 the length of head, sometimes reaching 
the ventrals, which may or may not extend to the origin of anal. Caudal forked. Caudal peduncle 
longer than deep. Olivaceous above, silvery below; a bluish-silvery lateral band; often a dark humeral 
blotch; an oblong blackish spot on the caudal peduncle, extending to the end of the middle caudal rays. 
Hab. Texas!9, Rio Grande®, Rio Nueces® (Smithsonian Inst.), and Rio Leona®.—MxExico, 
Rio Conchos in Chihuahua ° (Woolman), Rio Nazas in Durango *, Rio San Juan in 
Nuevo Leon*, Rio Conchos, Rio Soto Marina, and Rio Forlon in Tamaulipas 4 
(Meck), Rio Verde in San Luis Potosi * (Jordan, Meek), Rio Papaloapam and its 
tributaries+18; Rio Balsas and its tributaries!?414151617 (Boucard, Meek) ; 
GvaTEMALA, Rio Chisoy’, Rio San Gerdénimo §, Lake Peten® and Lake Yzabal ® 
(Salvin), Coban in Vera Paz 101! (Paris Mus.). 
Here described from a large series of specimens measuring up to 120 mm. in 
total length, including the types of 7. brevimanus (fig. 3) and 7’. petenensis (fig. 2), 
co-types of T. argentatus and of T. cobanensis, and examples collected at Cuernavaca 
by M. Boucard, corresponding to the 7. nitidus and 7’. fulgens of Bocourt, which were 
described from specimens obtained at this place by the same collector. 
4, Tetragonopterus angustifrons, sp. n. (Tab. XXVI. fig. 5.) 
Depth of body about 3 in the length, length of head 3% to 4. Snout subconical, $ as long as eye, the 
diameter of which is 3 in the length of head; interorbital width 33 to 33 in the length of head. 
Maxillary extending about to the vertical from anterior edge of pupil; 3 to 5 maxillary teeth. 14 to17 
gill-rakers on the lower part of the anterior arch. 34 to 38 scales in a longitudinal series, 7 or 8 in a 
transverse series from dorsal fin to lateral line, 6 or 7 between lateral line and base of ventrals. Dorsal 
11; origin behind the base of ventrals; longest ray 7 to $ the length of head; free edge of fin slightly 
convex. Anal 26-29, of 3 or 4 simple and 23 to 26 branched rays; free edge slightly emarginate. 
Pectoral # the length of head, about reaching the ventrals, which extend nearly to the anal. Caudal 
forked. Caudal peduncle longer than deep. Coloration as in the preceding species. 
Hab. Mexico (Sal/é). . 
Three specimens, the largest §0 mm. in total length. 
6. CHIRODON. 
Chirodon, Girard, Proc. Ac. Philad. vii. 1854, p. 199; Gunth. Cat. Fish. v. p. 332 (1864). 
About twelve species from South America and one from Mexico. 
