SOUTH AMERICAN NEMATOGNATHI. 183 



base of the occipital crest; distance between anterior 

 and posterior nares equals f the diameter of the eye. 



Maxillary barbel extending to the base of the caudal 

 or posterior margin of anal; mental barbels to base of 

 pectoral; postmental to near tip of pectoral. 



Eye I3 to 1|- in snout, 83 to 4 in head, | in interor- 

 bital. 



Mouth narrow, 3 in head, bordered by a broad lip; 

 depth of intermaxillary band of teeth about 3 in its width, 

 the outer row of teeth longer than the others. 



Gill-openings separate to a little in front of eye; gill- 

 rakers 4-}-12. 



Humeral process as wide as in clarias. 



Dorsal spine nearer snout than anal fin, measuring in 

 a straight line; rather strong teeth behind, 1\ in head. 



Adipose dorsal high and thin; its distance from the 

 dorsal longer than the base of the dorsal, about 41 in the 

 length. Caudal deeply forked, upper lobe slightly 

 longer, longer than head. 



Anal concave, the third ray longest, 1| in head. 



Ventrals li^ in head. Distance between the vent and 

 anal one-half a diameter of the eye shorter than head. 



Pectoral spine roughened in front, close-set recurved 

 hooks its whole length behind; 1\ in head. 



Upper half of body greenish-gray (olivaceous), below 

 the lateral line white; a dusky area behind the humeral 

 arch; upper anterior portion of body and sometimes top 

 of head with numerous small round dark spots. 



Dorsal fin dusky on its free half, and a series of dark 

 spots at its base. Other fins plain. 



Head 4^; depth 6J; D. I, 6; A. 12. 



XXII. Gen. Nov. ? 

 131. ? agassizii. 



Pirinampus agassizii Steindachner, SB. Ak. Wieu, Ixxiv, 1876, 

 Ichthyol. Beitr. iv, 57, pi. 12 (Para); Vaillant, Bull. Soc. Philom. 

 series 7, iv, 153, 1880 (Calderon). 



Habitat: Amazous. 



