440 MEMOIRS OF THE CARNEGIE MUSEUM 



Sternarchus albifrons Bloch and Schneider, Syst. Ichth., 1801, 497, pi. 94.— 



Eigenmann and Ward, Proc. Wash. Acad. Sci., VII, 1905, 162. — Eigenmann, 



Repts. Princeton Univ. Exp. Patagonia, III, 1910, 448. 

 Apteronotus passan Lacepede, Hist. Nat. Poiss., II, 1800, 209, pi. 6, fig. 3. 

 Sternarchus lacepedii Castelnau, Anim. Am. Sud, Poiss., 1855, 93, pi. 45, fig. 3 



(Surinam). 

 Sternarchus maximiliani Castelnau, Anim. Am. Sud, Poiss., 1855, 93, pi. 45, fig. 4 



(Urubamba) . 



Six specimens, 105-285 mm. Creek below Potaro Landing. (C. M. Cat. 

 No. 1760a-6; I. U. Cat. No. 12589.) 



Head 5.8-6.2; depth 5-5.5 in the length to the end of the anal; A. 155, 158, 

 164, 168, 170, respectively; snout 2.7-2.9, interorbital 3.25-3.5 in the head; eye 

 3.25-3.5 in the snout, 2.8-3 in the interorbital, 8.5-9 in the head; eleven to thirteen 

 rows of scales above the lateral line. 



Compressed and slightly elongate; width of the head 2.5-2.8, depth of head 

 in occipital region 1.25-1.5 in the greatest depth; anus on or a little behind the 

 vertical from the posterior margin of the eye; dorsal profile rather straight back of 

 the head, which slopes abruptly to the snout. 



Snout heavy, truncate, and rather short; mouth large, gape reaching to just 

 below the eyes; jaws strong, lower included on the sides; teeth minute and conical, 

 in two irregular rows in the lower jaw, and two circular patches (one on each side 

 of the median line) in the upper jaw. 



Caudal about 5, pectorals 1.2-1.4 in the head; origin of the anal in 

 front of the pectorals, about four times the eye behind the vertical from the 

 eye. 



Ground-color rusty black; a dirty white band about one and one-half times the 

 eye in width, extending in the median dorsal line from the tip of the snout to the 

 occiput; two creamy white vertical bands or rings completely encircling the 

 fish, the first beginning at about the one hundred and thirtieth anal ray and con- 

 tinuing to the end of the anal, the second (a smaller one) occurring at the origin of 

 the caudal; anal opening and sometimes the extreme tip of the caudal white; eye 

 in alcoholic specimens a bright china-blue; fins dead black. 



Porotergus genus nov. 



Type, Porotergus gymnotus sp. nov. Distinguished by the absence of scales 

 along the back to beyond the origin of the dorsal filament; scales along the lateral 

 line large; teeth in both jaws; other characters much as in Sternarchus. 



