SOUTH AMERICAN NEMATOGNATHI. 67 



sometimes keeled. Center of the fontanel over the 

 middle of eye, the fontanel not continued backward as 

 a groove. Occipital process, top of head, and humeral 

 process, granular; interorbital region Avith four ridges, 

 the inner ones bounding the fontanel, the outer ones 

 running obliquely backward from near the posterior 

 nasal opening. 



Eye S-3h in snout, 8|-10 in head, 4-4-0 in interocular. 



Maxillary barbels reaching to the base of the pectoral, 

 mentals to gill-opening, postmentals a little longer. 



UiDper jaw projecting a diameter of the eye or more, 

 the lip very wide, especially in front, making the nose 

 pointed; teeth of both jaws rather large, those on the 

 palate somewhat smaller; the depth of the intermaxillary 

 band 7-9 in its width; the mandibulary band very shal- 

 low; vomerine teeth none in three of the examples, a 

 small patch on one side in another specimen, and a 

 small patch on each side in another; palatine patches 

 triangular, produced backward. 



Gill-membranes meeting in an angle, forming a fold 

 across the isthmus. Gill-rakers 6+10. 



Distance of dorsal spine from snout 23-2| in the 

 length, the spine broken in the specimens studied. 

 Distance of adipose fin from the dorsal 3|-4 in the 

 length, adipose fin at least as long as the dorsal fin, 

 adnate. 



Caudal fin forked, the upper lobe longer, about 5 in 

 the length, the tips broken. 



Anal fin apparently longer than high, but the rays 

 are somewhat worn off. 



Ventral small. 



Pectoral pore large, slit-like. 



Color light brown above, somewhat smutty below from 

 the occurrence of minute scattered dots. 



Head 3|-3f ; depth 5§-6; D. I, 7; A. 18. 



