SOUTH AMERICAN NEMATOGNATHI. 233 



surface of the scutes covered with small ridges, each of 

 which ends in a short marginal spine. 



Caudal peduncle entirely covered with plates above 

 and below. 



Humeral process reaching to the 2nd or 3rd spine- 

 bearing scute, its surface in the young granular and a se- 

 ries of hooks near its lower margin; finely granular in 

 the old, and having a more or less prominent gran- 

 ular ridge. 



Distance of the dorsal fin. from the snout 2J in the 

 length; the dorsal spine as long as the head or longer, 

 its outer margin with upturned serrse, its sides deeply 

 grooved, its inner margin with serrae along the central 

 portion. Space between dorsal and adipose fins 5 in 

 the length. Base of the adipose shorter than the dorsal 

 fin. 



Caudal emarginate. Anal fin rounded, higher than 

 long, the fifth ray highest, 1J 2 in the head. 



Ventrals not reaching the anal If-lf in the head. 



Pectoral spine very strong, reaching beyond base of 

 ventrals, both surfaces striate, both margins strongly 

 serrate. Pectoral pore simple. 



Dark brown; a conspicuous light band along the mid- 

 dle of the sides, continued on the caudal fin and meet- 

 ing in front above the eyes; the brown below the lateral 

 band forms a broad band extending through the eye and 

 meeting in front of the white band; snout and head 

 below this band white; lower surface more or less thickly 

 covered with brown dots; dorsal white at base, a large 

 brown blotch near the tip; marginal and middle caudal 

 rays light, the others dark brown; anal and ventral fins 

 with a dark blotch; pectoral dusky, its spine and inner 

 rays light. Barbels brownish. 



Head3|-4; depth 4f-4i; D. I, 6; A. 11; V. 7; P.I, 7; 

 Lat. 1. 28-31. 



