^6 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxi. 



fontanelle a little beyond eye; top of head somewhat rougher than in 

 the preceding specimen; D. I, Y; distance from dorsal to adipose 8.66 

 in length of adipose, 2 A in base of dorsal; A. 10. 



25. LUCIOPIMELODUS PATI (Cuvier and Valenciennes). 

 PAT; PATI. 



Pimelodus pati Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, p. 176 

 Parana; La Plata; Corrientes; Buenos Aires. — Valenciennes in D'Orbigny, 

 Voy. Amer. Merid., V, 1847, p. 7; Atlas, pi. i, figs. 7-8 (Corrientes). — Peru- 

 gia, Ann. Mus. Civ. Stor. Nat. Geneva, 2d ser., X (XXX), 1890-91, p. 631 

 ("Rio della Plata"). 



Lurinpimelodus pall, Eigenmann and Eigenmann, Occ. Pap. Cal. Ac. Sci., I, 1890, 

 p. 106 (Rio Plata; Rio Branco near British Guiana). 



One specimen, total length 18.75 inches. Head 3.67 in length; 

 depth 5.22; eye 13.5 in head, 2.75 in intcror})ital, 6.75 in snout; snout 

 about 2 in head; interorbital 3.09 in width of head; maxilhuy l)arbel 

 1.59 in length without tail; postmental barbel 1.98, mental 1.12 in 

 head; pectoral 1.15; ventral 1.75; dorsal I, 6, height 3.11 in head; anal 

 11; adipose 2.95 in length without caudal, its' height 11.33 in its 

 length 



26. PSEUDOPIMELODUS ZUNGARO (Humboldt). 

 MANGTJRUYN. 



Pimelodus zungaro Humboldt, Observations, II, 1833, p. 170, pi. xlvi, fig. 1. 

 Pseuduphnelodus zungaro, Eigenmann and Eigenmann, Occ. Pap. Cal. Ac. Sci., 

 I, 1890, pp. 110, 112 (Rio Plata; Rio Magdalena and the region between). 



One specimen 15.25 inches total length. 



Head wider than long, 3.61 in length without caudal; width of head 

 about 3.4 in length without caudal; eye 17.6 in head, 8.4 in interor- 

 bital; maxillary barbel 1.42 in head; length of base of adipose 2 in 

 head; D. I. 6; A., 8. 



Family PYGIDID^. 



27. PYGIDIUM AREOLATUM ( Cuvier and Valenciennes). 

 ANGTTILLA. 



Trichomi/cterua areolatus Cuvier and Valenciennes, Hist. Nat. Poiss., XVIII, 



1846, p. 492, Riviere de San Jago. 

 Pygidium areolatum, Eigenmann and Eigenmann, Occ. Pap. Cal. Ac. Sci., 1, 



1890, p. 330(Mapocho, Chile).— Berg, Anal. Mus. Nac. Buenos Aires, IV, 



1895, p. 143 (Catamarca). 



Nineteen specimens, 2.18 to 6.5 inches long, easily referable to this 

 species. In some of the proportional measurements there is consider- 

 able individual variation not depending upon the size of the tish, which 

 the following table indicates. Six of these were labeled from Rio 



