246 Annals of the Carnegie Museum. 



10. Pristobrycon scapularis (Gunther). 



Serrasalmo scapularis Gunther, Cat. Fishes Brit. Mus., Vol. V, 1864, p. 368 



(British Guiana); Pellegrin, Bull. Mus. d'Hist. Nat., 1899, p. 157 (Apure). 

 Pygocenirus scapularis Eigenmann & Eigenmann, Proc. U. S. Nat. Mus., Vol. 



XIV, 1891, p. 69; Ulrey, Ann. N. Y. Acad. Sci., Vol. VII, 1895, p. 297 (Marajo); 



Eigenmann & Ogle, Proc. U. S. Nat. Mus., Vol. XXXIII, 1907, p. 35 (South 



America). 

 Serrasalmo coccogenis Fowler, Proc. Acad. Nat. Sci. Phila., 191 1, p. 428, fig. 4 



(La Pedrita, on the Cano Uracoa, Venezuela). 



Habitat. — British Guiana, Orinoco, Amazon to Para. 

 5799 0,-b- C. M. 140-197 mm. Manaos, Dec. 9, 1910. Haseman. 



Very similar to Serrasalmo aureus, but not so deep, and to calmoni, 

 which has a black bordered caudal. 



Head 3.4-3.66 to end of lateral line; depth 1.7-1.8; D. 16 or 17; 

 A. 32 or 33; serrae 26+1 and 28 + 1; interorbital 2.25-2.5 in the 

 length of the head. Distance from dorsal to caudal fulcra equals 

 length of head, much greater than base of dorsal; origin of dorsal 

 about equal to distance from tip of snout to end of lateral line; base 

 of anal a little longer than head; suture between first and second 

 suborbitals vertical; second suborbital leaving a naked area nearly 

 half as wide as bone in the larger and but little narrower than the 

 bone in the smaller specimen; palatines roughened more or less and 

 with a tooth-like tubercle. Caudal pale-edged; upper parts of sides 

 with small spots. 



In the suture between the first and second suborbitals these speci- 

 mens differ from the specimens from Guiana in which it extends down- 

 ward and forward. 



II. Pristobrycon aureus (Agassiz). 



Serrasalmo aureus Agassiz, Selecta Genera et Spec. Pise, 1829, p. 72, tab. 29; 

 CuviER & Valenciennes, Hist. Nat. Poiss., Vol. XXII, 1848, p. 282; Castel- 

 NAU, Anim. Amer. Sud, Poiss., 1855, p. 71 (Goyaz); ? Muller & Troschel, 

 in Schomburgk's Reisen, Vol. Ill, 1848, p. 637 (Essequibo, Rupununi); Kner, 

 Characinen, Vol. II, 1859, p. 35 (Rio Vaupe, Matto Grosso). 



Serrasalmo gymnogenys Gunther, Cat. Fishes Brit. Mus., Vol. V, 1874, p. 371. 

 (River Capin, British Guiana); Eigenmann & Eigenmann, Proc. U. S. Nat. 

 Mus., Vol. XIV, 1891, p. 60; Ulrey, Ann. N. Y. Acad. Sci., Vol. VII, 1895. 

 p. 298 (Marajo); ? Perugia, ^ Ann. Mus. Civ. Stor. Nat. Geneva, 2a, Vol. X, 

 1891, p. 650 (Resistencia, Chaco Centrale): Pellegrin, Bull. Mus. d'Hist. 

 Nat., Vol. V, 1899, p. 157 (Apure); Eigenmann, Reports Princeton Univ. Exp. 

 Patagonia, Vol. Ill, 1910, p. 442; Memoirs Carnegie Mus., Vol. V., 1912, p. 381 

 (Rockstone; Wismar; Tumatumari; Crab Falls below Packeoo). 



' It is very probable that Perugia had either Serrasalmo marginatus, or humeralis. 



