SOUTH AMERICAN NEMATOGNATHI. 197 



head at the rictus 2 in its length. Occipital process 

 reaching dorsal plate. 



Maxillary harbel past ventral (past tip of caudal in 

 young); mental barbels half way to pectoral (past ventral 

 in young); postmentals to base of pectoral (to base of cau- 

 dal in young). 



Eye 8-18 in head, 4-8J in snout, 2|-5J in interor- 

 bital, 1|-2J diameters behind the rictus. 



Teeth of the upper jaw in a broad band, the outer 

 ones similar to those in the lower jaw, the inner ones 

 long, slender, depressed and freely movable; those of 

 the vomer much smaller, the teeth on the palatines still 

 smaller. 



Gill-membranes separate to below the angle of the 

 mouth; gill rakers fine, scarcely shorter than the eye, 

 6-9+15-24. 



Skin on sides of head and on snout reticulate, the re- 

 ticulations sometimes continued on nape and along 

 anterior portion of the lateral line. 



Dorsal spine equidistant from tip of snout and middle 

 of adipose, serrated behind, and near its tip in front in 

 young, 1J in head. Adipose fin longer than the anal. 



Caudal fin very deeply lobed, the lobes filiform, the 

 upper in the young equal to half the length of the body 

 or longer, the rays normal. Ventrals one-half their 

 length beyond the vent (one-fourth in adult), lf-3 in 

 head. The distance from the vent to the anal equals 4 

 diameters of the eye (11 in the adult); from the vent to 

 the caudal two-fifths more than length of head. 



Pectoral spine lf-2 in head. 



Uniform brownish. 



Head 3J-3J; depth 5J; Br. 11 or 12; D. I, 6; A. 13. 



The specimens examined are from Tabatinga; Para; 

 Porto do Moz; Avary; Rio Puty; Juiz de Fora, on. the 

 Parahyba; Serpa; Rio Negro. The largest 1.19 m. 



