BULLETIN OF THE UNITED STATES FISH COMMISSION. 41 



Head 3£ (4); depth 6 (7); width of head 4; length (29252) 11 inches. 

 D. I, 7 j A. 4, 13. 



Body rather long and low; the head long, broad, and much depressed, 

 much broader than deep. Eye very .small, about 10 in head, placed 

 well above the mouth. Interorbital space 2 in head; snout 3^; breadth 

 of mouth 2. 



Mouth large, with thickish lips, the upper jaw considerably pro- 

 jecting. Teeth all villiform, rather pointed. Vomerine patches rather 

 large, roundish, usually fully confluent into a trapezoidal band, with- 

 out division on the median line, and separated by a very narrow 

 groove from the palatine bands. Palatine bands very large, broadly 

 triangular, with a backward prolongation from the inner margin, as in 

 A. brandti. (Teeth on vomer and palatines all forming one continuous 

 baud in old specimens, according to Steindachner). Bands of teeth in 

 jaws broad, the jaws strong. Barbels rather short and very slender, 

 the maxillary barbels reaching little past base of pectoral; outer mental 

 barbels about reaching gill-opening ; inner about as long as snout. 



Ante-dorsal shield short, crescent-shaped, rough, but without median 

 keel. Occipital process long, narrowly triangular, its edges straight, 

 its length one-fourth to one-half more than its width at base, its 

 median line sharply keeled. 



Fontanelle broad and shallow, its posterior end obtuse or almost 

 truncate, its tip not prolonged in a groove, its edge bounded by a bony 

 ridge, which is not granulated iu front of middle of eye ; end of fonta- 

 nelle about midway between tip of snout and front of dorsal ; its 

 greatest width about equal to length of eye. Shields of head all very 

 coarsely granular, the roughnesses extending forward about to the eye. 

 Gill-membranes forming a very broad free fold across isthmus. 



Dorsal spine moderate, a little more than half head, about equal to 

 pectoral spine. Humeral process triangular, granular, not quite two- 

 fifths length of pectoral spine. Axillary pore obsolete. Adipose tin 

 long and low, its posterior margin little free. Caudal short and broad, 

 the upper lobe longest, If in head. Anal and ventrals rather small, 

 the vent close behind the latter. 



Color dark brown, with bronze reflections ; belly white. Fins all dusky 

 in one specimen, in the other mostly pale. Maxillary barbels dusky : 

 others pale. 



Two large specimens were obtained at Panama. 



SPECIMENS IN UNITED STATES NATIONAL MUSEUM. 



29252. Panama. Gilbert, 

 29413. Panama, Gilbert. 



7. Arius insculptus, sp. nov. 



Head 4 (4f); depth 5f (6|); width of head 4f. Length (29415) 13£ 

 inches. D. 1, 6; A. 4, 14. 

 Body moderately elongate, little compressed, the caudal peduncle 



