SOUTH AMERICAN NEMATOGNATHI. 115 



short, but meeting the longer dorsal plate. Large round 

 pores on the head, most numerous on the snout and 

 chin. 



Eye small, 2i in the snout, 8J in the head, 3 in the 

 iiiterorbital. 



Barbels all short, those of the maxillaries extending 

 little, if any, beyond middle of the pectoral fin. 



Mouth more than half as wide as the length of the 

 head; intermaxillary band of teeth with a sharp, back- 

 ward projecting angle; mandibulary band 

 of teeth shallower than the intermaxillary 

 band, about as deep as one diameter of the 

 eye, scarcely deeper in front than at the 

 sides. 



Humeral process almost horizontal, strong, triangular, 

 not reaching to the middle of the pectoral. 



Distance of the dorsal spine from end of snout 2J in 

 the length. Dorsal spine toothed on the outer margin, 

 stout, 2 in head, the rays higher, nearly uniform. Dis- 

 tance of the adipose fin from the dorsal longer than the 

 length of the dorsal. Adipose about as long as the dorsal 

 fin. 



Caudal fin long, scarcely shorter than the head, 

 rounded. 



Anal fin beginning and ending a little in front of the 

 anterior and posterior ends of the adipose; the tips of the 

 anal rays extending to the base of the caudal when laid 

 back. 



Ventrals inserted under the vertical from the last dor- 

 sal ray, IJ-lf in the head. 



Pectoral fin extending to the ventrals in young, much 

 shorter in adult specimens; the spine 1J in the head, 

 not much shorter than the longest ray, very much de- 

 pressed, the teeth equally strong and long on the inner 

 and outer margins of the spine, those on the outer mar- 



