SOUTH AMERICAN NEMATOGNATHI. 457 



somewhat pointed; interinaxillaries rudimentary; patches 

 of minute teetli in the jaws. Lower lip with a broad free 

 margin which is angularly incised at the symphysis. 



Gill-openings continued downward to the middle of 

 the external coracoid, the isthmus measuring 2-3 orbital 

 diameters. 



Sides entirely covered with two series of laminse which 

 are margined with minute bristles; a series of azygous 

 plates behind the dorsal fins divides the lateral laminae; 

 ventral surface with a rather broad naked area. Coracoid 

 and clavicle joined for their whole length; the coracoid 

 processes diverging posteriorly leave a goblet-shaped 

 naked area between. 



Lateral line present, at least anteriorly, consisting of 

 a simple tube extending across the lower portion of the 

 superior series of lamina?, continued forward as pores 

 situated in pits along the sides of the head above the eyes. 



Distance of the dorsal spine from the snout 2-21 in the 

 length; dorsal spine short and flat, 2-3 times as high as 

 the eye; second dorsal ray highest, the margin of the fin 

 rounded. 



The rays of all the fins roughened with minute bristles. 

 Adipose fin triangular, composed of a curved spine 

 about as high as the dorsal spine and a thin adnate 

 membrane. 



Outer rays of the caudal thickened, the fin emarginate, 

 3-4 in the length. 



Anal with a spine similar to that of the dorsal fin, the 

 margin of the fin obliquely truncate, the second ray 2-3 

 times as high as the last ray, reaching base of caudal fin. 



Ventral fins inserted opposite the third dorsal ray, 

 their length IJ-li in the head. 



Pectoral spine very variable, 3-6 in the length, its 

 outer surfaces thickly covered with short bristles, its 

 inner margin either smooth or serrate, its tip sharp in 



