EIGENMANN: the freshwater fishes of BRITISH GUIANA 377 



Key to the Guiana Species of Chalcinus. 

 n. Six scales between the dorsal and the lateral line; twenty to twenty-five rakers on the lower limb of the 

 first gill-arch; depth in the largest 3.3-3.4 in the length; caudal peduncle slender, its width equal to 



half of its depth in the largest; lateral line 40-43; A. 27-30 elongatus. 



an. Five scales between the dorsal and the lateral line; tliirty to forty-two rakers on the lower limb; depth in 

 the largest 3 in the length; caudal peduncle compressed, its width equal to one-third of its depth in 

 the largest; pectoral much broader than in the preceding species; lateral Une 3.5-37; A. 26 or 27; 

 origin of anal under last dorsal ray rotundatus. 



230. Chalcinus elongatus Giinther. 



Chalcinus elongatus Gunther, Catalogue, V, 1848, 342. — Steindachner, "Ich- 

 thyologische Beitrage," v, 1876, 54 (Teffe; Peruvian Amazon); "Flussfische 

 Stidamerika's," i, 1879, 9 (Orinoco near Ciudad Bolivar). — Garman, Bull. 

 Essex Inst., XXII, 1890, 6 (Arary; Cameta; Gurupa; Iga; Jose Fernandez; 

 Jutahy; Lago Alexo; Lake Hyanuary; Lake Jose Assu; Manacapuru; Manaos; 

 Montalegre; Obidos; Para; Porto do Moz; Rio Negro; Santarem; Silva, Lake 

 Saraca; Tabatinga; Teffe; Tonantins; Villa Bella). — Eigenmann and Eigen- 

 MANN, Proc. U. S. Nat. Mus., XIV, 1891, 56. — Eigenmann, Repts. Princeton 

 Univ. Exp. Patagonia, III, 1910, 440. 



One specimen, 213 mm. Aruka River. (C. M. Cat. No. 1999a.) 

 Two specimens, 200 mm. Koreabo Rubber Plantation. (C. M. Cat. No. 



2000; I. U. Cat. No. 12247.) 



Seven specimens, 93-142 mm. Creek in Mora Passage. (C. M. Cat. No. 



2057a-c; I. U. Cat. No. 12250.) 



Ten specimens, 107-115 mm. Trenches in Morawhanna. (C. M. Cat. No. 



2058a-fc; I. U. Cat. No. 12248.) 



231. Chalcinus rotundatus (Schomburgk). (Plate LV, fig. 1.) 



Chalceus rotundatus Schomburgk, Fishes Brit. Guiana, I, 1840, 209 (Padauiri). 



Chalcinus brachypo7nus Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 

 1848, 259 (Mana; Essequibo).— GtJNTHER, Catalogue, V, 1864, 339 (Esse- 

 quibo). — Steindachner, " Ichthyologische Beitrage, v, 1876, 49 (Demerara; 

 Santarem; Villa Bella).— Pellegrin, Bull. Mus. d'Hist. Nat., V, 1899, 157 

 (Apure).— Fowler, Proc. Acad. Nat. Sci. Phila., 1906, 1449, fig. 43 (Dem- 

 erara River). 



Chalceus angulatus (not of Spix) Muxler and Troschel, in Schomburgk, Reisen, 

 III, 1848, 635 (Essequibo and Rupununi). 



Chalcinus gUntheri Garman, Bull. Essex Inst., XXII, 1890, 4 (San Francisco). — 



