TETEAGONOPTEEFS. 171 



T. (eneus is very closely allied to T. rutilus, Jenyns, which ranges from Venezuela to 

 Montevideo, and it is practically impossible to distinguish between young examples of 

 the two species. When adult specimens are compared, however, the distance between 

 the eye and the upper edge of the lower limb of the praeopercle, just behind the arti- 

 culation of the lower jaw, is seen to be considerably less in T. rutilus than in T. aeneus, 

 being equal to J the vertical diameter of the eye in the former and f of the same in 

 the latter species. 



Steindachner had formerly given the name T. fischeri to the specimens which he 

 described and figured as T. panamensis. Astyanax emperador, Eigenm. & Ogle (Proc. 

 U.S. Nat. Mus. xxiii. 1907, p. 26), from Panama, is said to differ from A. fischeri in 

 the smaller scales (39 to 45 instead of 34 to 37) in a longitudinal series. 



2. Tetragonopterus macrophthalmus, sp. n. (Tab. XXVI. fig. 4.) 



Tetragonopteriis ceneus (part.). Meek, Publ. Columbian Mus., Zool. v. 1904, p. 86 \ 

 Astyanax rutilus, Tariety ?, Eigenmann & Ogle, Proc. U.S. Nat. Mus. xxxiii. 1907, p. 23 ". 



Depth of body 2j to 3| in the length, length of head 3| to 4-|. Snout obtuse, decnrved, i to | as long as 

 ej-e, the diameter of -which is 2i to 'S in the length of head ; interorbital width i;| to 3 in the length of 

 head. Maxillary extending nearly to the vertical from anterior edge of pupil ; to 4 maxillary teeth. 

 10 to 12 gill-rakers on the lower part of the anterior arch. 34 to 40 scales in a longitudinal series, 6 to 

 8 in a transverse series from dors<al fin to lateral line, 5 or 6 between lateral line and base of ventral. 

 Dorsal 10-12 ; origin behind the base of ventrals ; longest ray as long as the head ; free edge of the fin 

 nearly straight. Anal 23-29, of 3 or 4 simple and 20 to 25 branched rays ; free edge usually emargiuate. 

 Pectoral about as long as the head, usually reaching the ventrals, which nearly or quite reach the origin 

 of anal. Caudal forked. Caudal peduncle longer than deep. Coloration as in the preceding species. 



Hah. Mexico (Salle), Motzorongo ^ in Vera Cruz i " {Meelc, Gadow). 



Several specimens, measuring up to 130 mm. in total length, 



Meek's description is evidently based on examples of this species, but he also had 

 the true T. ceneus in his collections. 



3. Tetragonopterus mexicanus. (Tab. XXVI. figg. 2, 3.) 



Tetragonopterus mexicanus, Filippi, Rev. Mag. Zool. 1853, p. 166'; Steind. Sitzungsb. Ak. Wien, 



Ix. 1869, p. 299, t. 4=; Jord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1896, p. 335'; Meek, 



Publ. Columbian Mus., Zool. v. 1904, p. 85 '. 

 Tetragonopterus argentatus, Baird & Girard, Proc. Ac. PLilad. 1854, p. 27 ' ; Jord. & Everm. t. c. 



p. 336 \ 

 Tetragonopterus fasciatus (part.), Gunth. Cat. Fish, v- p. 322 (1864) \ 

 Tetragonopjterus brevimanus, Giintli. t. c. p. 325 ". 

 Tetragonopterus petenensis (part.), Giiuth. t. c. p. 326°. 

 Tetragonopterus cobanensis, Bocourt, Aun. Sei. Nat. (5) ix. 1868, p. 62"; Vaill. & Pellegr. Bull. 



Mus. Paris, 1903, p. 323 ". 

 Tetragonopterus oaxacanensis, Bocourt, 1. c. '' ; Vaill. & Pellegr. t. c. p. 324 '\ 

 Tetragonopterus nitidus, Bocourt, 1. c."; Vaill. & Pellegr. 1. c.''. 



Z2 



