260 Annals of the Carnegie Museum. 



i6 17 , 33 34 35 36 37 30 31 32 33 34 35 , ^, 



— , --; A. — , — , — , — , — ; serrae — , — , — , — , — , — ; length 

 56 22412 112142 



to end of lateral line i. 7-2.1. 



26. Serrasalmo marginatus Valenciennes. 



Serrasalmo marginatus Valenciennes in d'Orb. Voy. Amer. Merid, Poiss., 1847, 

 p. 10, pi. 10, fig. i; CuviER & Valenciennes, Hist. Nat. Poiss., Vol. XXII, 

 1848, p. 277 (Corrientes) ; Kner, Characinen, Vol. II, 1859, p. 32 (Guapore, 

 Cuyaba); Gunther, Cat. Fishes Brit. Mus., Vol. V, 1864; Ann. & Mag. Nat. 

 Hist., 1880, p. 13 (La Plata); Eigenmann & Eigenmann, Proc. U. S. Nat. Mus., 

 Vol. XIV, 1891, p. 60; Ulrey, Ann. N. Y. Acad. Sci., Vol. VII, 1895, p. 297 

 (Brazil); Berg, Com. Mus. Nac. Buenos Ayres, i, 1899, p. 166 (Buenos Aires); 

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

 guay). 



Serrasalmo humeralis Castelnau {non Cuvier & Valenciennes), Anim. Am. Sud, 

 Poiss., 1855, pi. 37, fig. 2; Eigenmann & Kennedy, Proc. Acad. Nat. Sci., 

 Phila., 1903, p. 528 (Rio Paraguay and Arroyo Trementina); Eigenmann, 

 Reports Princeton Univ. Exp. Patagonia, Vol. Ill, 1910, p. 442. 



Serrasalmo iritans Peters, Mb. Ak. Wiss., Berlin, 1877, p. 472 (San Fernando de 

 Apure); Eigenmann & Eigenmann, Proc. U. S. Nat. Mus., Vol. XIV, 1891, 

 p. 60; Ulrey, Ann. N. Y. Acad. Sci., Vol. VII, 1895, p. 298 (Marajo). 



Serrasalmo iridopsis Ulrey, {non Cope) N. Y. Acad. Sci., Vol. VII, 1895, p. 298 

 (Tocantins). 



Distribution. — La Plata basin, Orinoco, Amazons. 



5771 a. C. M. 76 mm. Berlin, Rio Mamore, Sept. 15, 1909. Hase- 

 man. 



D. 15; A. 34; serraj 34. 



5772 a. C. M. 70 mm. San Joaquin, Sept. 5, 1909. Haseman. 

 D. 16; A. 34; serra? 33. 



5773 a. C. M. 62 mm. Caceres, May 26, 1909. Haseman. 

 D. 16; A. 34; serrse 28. 



5794 a-c. C. M. 45-66 mm. Rio Jauru, June 2, 1909. Haseman. 



These specimens are all young and the identification is more or less 

 doubtful. They may be the young of humeralis in which the terminal 

 caudal bar has not yet developed. They differ otherwise from young 

 humeralis in having the opercle dark below its middle. 



Subfamily MYLIN.^. 



Body compressed, deep; ventral surface with serrse; teeth of the 

 premaxillary in two series; mandible with a single series of teeth and 

 sometimes a pair of subconical teeth behind and in contact with the 

 symphyseal pair of teeth; no teeth on the palate or on the maxillary; 



