THE AMERICAN TETRAGONOPTERINAE. 95 



emarginate, its origin behind the vertical from the base of the last dorsal ray; 

 ventrals reaching anal, pectorals about one scale beyond base of ventrals. 



Straw-color in alcohol, a narrow silvery, lateral band; sometimes a faint, 

 always minute, humeral spot; a black stripe along base of anal, along ventral 

 surface of caudal peduncle, then upward and backward along the posterior 

 margin of the upper caudal lobe. This black stripe is diagnostic for the species, 

 although it is at times (Penedo specimens) scarcely perceptible. It is especially 

 conspicuous in the specimens from Queimadas. 



19. Moenkhausia dichroura (Kner). 

 Plate 8, fig. 3; Plate 15, fig. 1; Plate 95, fig. 3; Plate 100, fig. 3. 



Telragonopterus dichrourus Kner, Characinen, 1859, p. 41, tab. 9, fig. 21 (Rio GuaporS; Caigara; Para- 

 guay); Guntheb, Cat. fishes Brit, mus., 1864, 5, p. 324; Eigenmann & Eigenmann, Proo. U. S. 

 N. M., 1891, 14, p. 53; Ulrey, Ann. N. Y. acad. sci., 1895, 8, p. 279; Perugia, Ann. Mus. civ. storia 

 nat. Genova, 1891, ser. 24, 10, p. 45 (Chaco Centrale); Boulenger, Trans. Zool. soc. Lond., 1896, 

 14, p. 35 (San Luis and Descalvados) ; Boulenger, Boll. Mus. univ. Torino, 1897, 12, no. 279, p. 4 

 (San Lorenzo); 1900, 15, no. 370, p. 2 (Urucum); Eigenmann & Kennedy, (in part), Proc. 

 Aead. nat. sci., Phil., 1903, p. 522 (Ascuncion; Arroyo Trementina). 



Moenkhausia dichrourus Eigenmann, Ann. Carnegie mus., 1907, 4, p. 138, pi. 41, fig. 1 (Tuyuyu; 

 Corumba; Asuncion); Rept. Princeton univ. Exped. Patagonia, 1910, 3, p. 438. 



Moenkhausia dichroura Eigenmann, Mem. Carnegie mus., 1912, 5, p. 326. 



Habitat. — Guiana south to Bolivia, Paraguay and the Paranagua. 



Catalogue Number of Length 



number specimens in mm. Locality Collector 



3698 C. • 5 28-62 Rio Jauru Haseman 



3699 C. 3 44-91 Puerto Suarez Haseman 

 3701 C. 5 53-75 San Joaquin, Bolivia Haseman 



3703 C. 2 43-52 San Joaquin Haseman 



3704 C. 2 51-60 Corumba Haseman 



3705 C. 2 56-60 Bastos Haseman 



3706 C. 8 52-66 Asuncion Haseman 



3707 C. 2 62-65 Arequa Haseman 



3708 C. 26 40-06 Villa Hays Haseman 



3709 C. 16 52-67 Lagoa de Paranagua Haseman 

 3738 C. 2 58-62 Santarem Haseman 



1345 C, 11861 I. 2 59-62 Warraputa Cataract, Essequibo River Eigenmann 



1346 C. 2 28-65 Crab Falls, Essequibo River Eigenmann 



1347 C, 11S62 I. 12 58-63 Konawaruk, Essequibo River Eigenmann 



These specimens are without exception more slender than the types. In 

 shape the types resemble M. barbouri, from which they differ in the number of 



