SOUTH AMERICAN NEMATOGNATHI. 381 



nutely granular. Superciliary edges raised, interorbital 

 narrow, the loreal region convex. 



Orbit with a shallow notch behind. 



Eye 2J-4 in the snout, 5-7 in the head, |--| in the 

 interorbital. Snout pointed, its margin and tip granular. 



Lower surface of snout and head naked. Teeth well 

 developed, numerous in both jaws; upper lip with a 

 fringe of long cirri; lower lip closely covered with larger 

 and smaller papillae in the female, short in the male, 

 covering the entire under surface of the head. Barbels 

 fringed, the free portion about equal to an orbital diam- 

 eter. 



Sides of the belly with a series of rather large scutes, 

 a large anal plate, the central portion of the belly en- 

 tirely covered with small scutes in the adult, entirely 

 naked in the young (.065 m.), with two median series 

 of scutes in example .10 metre long. The anal plate in 

 the adult is bordered in front and laterally by a series of 

 small plates which are larger in the <3 than in the ? . 



Lateral keels scarcely developed, coalescing on about 

 the 25th scute. 



No pectoral pore. 



Distance of the dorsal fin from tip of snout 3J-3 ; V in 

 the length ; dorsal fin about twice as high as long. Caudal 

 emargiriate, its outer rays scarcely produced. 



Anal fin well developed. Ventral fins emargiriate, the 

 3rd and 4th rays higher than the 1st and 2nd, the spine 

 produced, reaching base of anal. 



Pectorals emarginate, reaching beyond base of ventrals. 



Head and body with small roundish dark spots, those 

 on the tail arranged in series, one along the median line 

 of back, one between the dorsal and lateral plates, an- 

 other between the lateral keels; the spots more conspicu- 

 ous in the female than in the male; the fins similarly 

 spotted except the anal and sometimes the ventrals; tip 



