110 FISHES OF WESTERN SOUTH AMERICA 
the skin; pectoral spine much stouter, about I, 9; adipose short, just exceeding the 
interorbital, its depth 2.5 in its length, very fleshy; caudal broad, full, its lobes 
deeply cleft, and rounded. 
Color in alcohol a rich, soft brown becoming nearly black in the middle of the 
white-bordered bands, and a lighter, diffuse brownish on head and caudal fin, yellow 
on other median fins, and nearly white on paired fins which are low and horizontal. 
Bands about 20 in number cross the back and reach the points of widest diameter, 
mostly beyond the lateral line, and diminishing toward the caudal; continued up- 
ward brokenly on the adipose. Series of spots on the dorsal rays not so dark, 
numerous irregular rows on the caudal fin, fewer and smaller on the anal; the paired 
fins unmarked. 
Genus 19: PHRACTOCEPHALUS Agassiz 
Phractocephalus Agassiz, 1829, Sel. Gen. et Spec. Pisce. Bras., 22, bicolor = hemiliopterus; 
Eigenmann and Kigenmann, 1890, Occ. Papers Cal. Acad. Sei., I, 188; 
Eigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 390; 
Eigenmann, 1912, Mem. Carnegie Mus., V, 178. 
Type: Stlurus hemiliopterus Bloch and Schneider 
The range that of the single species 
Large nematognath fishes having rather short body and very broad head; upper 
portion of head with granulations arranged in a vermiculated pattern; occipital 
process broad, semicircular, rounded on its caudal margin, not reaching to dorsal 
plate; latter broadly reniform; adipose fin somewhat rayed distally; vomerine teeth 
contiguous to palatine, in large pentagonal patches; barbels subterete; caudal 
forked. 
52. PHRACTOCEPHALUS HEMILIOPTERUS (Bloch and Schneider) 
Silurus hemiliopterus Bloch and Schneider, 1801, Syst. Ichth., 385. 
Phractocephalus hemiliopterus Cuvier and Valenciennes, 1840, Hist. Nat. Poiss, XV, 3, pl. 421; 
Castelnau, 1855, Anim. Amér. Sud, Poiss., 47, pl. xv, fig. 4; 
Giinther, 1864, Cat. Fish. Brit. Mus., V, 110; 
Cope, 1878, Proc. Amer. Phil. Soc., XVII, 674, Peruvian Amazon; 
Eigenmann and Eigenmann, 1890, Occ. Papers Cal. Acad. Sci., I, 188; 
digenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 390; 
Eigenmann, 1912, Mem. Carnegie Mus., V, 178. 
Phractocephalus bicolor Agassiz, 1829, Sel. Gen. et Spec. Pisce. Bras., 23. 
Amazon and Maranon northward 
15951, 1, 310 mm., Iquitos, Morris, 1922. 
Specimens of appropriate size for preservation were not collected by Allen. 
The largest, about four feet in length, was harpooned on the Rio Puinagua at 
Bretafa, in the eddy at the outlet of the Rio Pacaya. Others approaching that 
size were seen at the Iquitos market. 
