42 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



slender and short. Head shortish, low and broad, anteriorly depressed. 

 Eye rather large, G.J in head, placed rather high ; interorbital space flat 

 and nearly smooth, 2 in head; snout 3; breadth of month \$. Sneut 

 very bluntly rounded, almost truncate in front. 



Mouth large; teeth all villiforrn; vomerine bauds of teeth large (fully 

 confluent with each other in the type, partly separated in smaller exam- 

 ples), and with the large, club-shaped band on the palatines, from which 

 they are separated by a slight furrow and constriction; palatine band 

 of teeth with a backward prolongation. Premaxillary band of teeth 

 large. Maxillary barbel long, somewhatcompressed, extending to middle 

 of pectoral spine. Outer mental barbel reaching base of pectoral spine; 

 inner 2 in head. 



Ante-dorsal shield short, crescent-shaped, without median keel, its 

 tips produced, its length on the median line about two- fifths the length 

 of one of its halves. Occipital process about as broad at base as long, 

 with a moderate median keel, its lateral margins somewhat concave. 

 Fontanelle becoming gradually contracted at a point a little nearer base 

 of dorsal than top of snout, thence forming a narrow groove, which ex- 

 tends to within the diameter of the pupil of the base of the occipital 

 process, this groove sometimes nearly obsolete. Greatest width of fon- 

 tanelle about three-fifths diameter of eye. Granulated stria? extending 

 along the sides of the fontanelle to a point opposite or in front of middle 

 of eye. 



Shields of head finely and evenly granulated, the roughnesses more 

 uniform than usual and many of them arranged in lines, especially an- 

 teriorly. Opercle not striate, the skin marked with fine vermiculations. 

 Gill-membranes forming a broad fold across the isthmus. 



Dorsal and pectoral spines long, about equal, 1^ in head. Xo axillary 

 pores. Humeral process very large, triangular, finely granular, about 

 half as loug as pectoral spine. Adipose fin large, without free tip. 

 Upper lobe of caudal longest, 1£ in head. Anal and ventrals moderate, 

 the vent close behind the latter. 



Color rather pale; belly pale. Fins and barbels all pale, or but 

 slightly tinged with dusky. 



A single adult male specimen was obtained at Panama. Two smaller 

 ones are in the Museum collection, also from Panama. 



SPECIMENS IN UNITED STATES NATIONAL MUSEUM. 



29415. Panama, Gilbert. 



30977 (2). Panama. Kev. Mr. Powell. 



8. Arius planiceps Steindachner. 



Ariua planiceps Steindachner, Ichth. Beitr. iv, 2(i, taf. iv, 1875 (Panama; 



Altata). 

 ? Sciadcs iroseheli Gill, Proc. Ac. Nat. Sci. Phila. 1863, 171 (Panama). 



Habitat. — Pacific coast of tropical America; Altata; Panama. 

 Head 4 (4|); depth o£ (5§); width of head 5; length (29417) 11 

 inches. D. I, 7 ; A. 4, 13. 



