2766 Bulletin //, United States National Museum. 



broad, ;interiorly depressed. Eye rather large, 6i iu head, placed rather 

 high. Interorbital space flat and nearly smooth, 2 in head; snout 3; 

 breadth of month Ij'V; snout very bluntly rounded, almost truncate in 

 front. Mouth large; teeth allvilliform; vomerine bands of teeth large 

 (fnlly confluent with each other in the type, partly separated in smaller 

 examples), 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; prcraaxillary band of teeth 

 large; maxillary barbel long, somewhat compressed, extending to middle 

 of pectoral spine; outer mental barbel reaching base of pectoral spine, 

 inner 2 iu head. Dorsal shield short, crescent-shaped, without median 

 keel, its tips produced, its length on the Jiicdian line about | the length 

 of 1 of its halves. Occipital process about as broad at base as long, 

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

 fontanel becoming gradually contracted at a point a little nearer base 

 of dorsal than tip of snout, thence forming a narrow groove, which 

 extends to within a diameter of the pupil of the base of the occipital 

 process; this groove sometimes nearly obsolete; greatest width of fon- 

 tanel about f diameter of eye. Granulated striae extending along the 

 sides of the fontanel to a point opposite or in front of middle of eye. 

 Shield of head finely and evenly granulated, the roughnesses more uniform 

 than usual, and many of them arranged in lines, especially anteriorly; 

 opercle not striate, the skin marked with fine vermiculations; gill mem- 

 branes forming a. 1)road fold across the isthmus. Dorsal and pectoral 

 spines long, about equal, 1|^ in head. No axiliary pores; humeral process 

 very large, triangular, finelj'^ granular, about \ as long as pectoral 

 spine ; adipose fin large, without free tip ; upper lobe of caudal the longer, 

 li 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 was obtained by Dr. Gilbert 

 at Panama. Two smaller ones are in the Museum collection, also from 

 Panama. (Jordan «fc Gilbert, Bull. U. S. Fish Coram., ii, 1882, 41.) 



182. XETUMA PLA3VICEPS (SteJDdachner). 



Head 4 (4^, in total) ; depth 5^ (51) ; width of head 5. D. I, 7; A. IV, 13. 

 Length (29417) 11 inches. Body comjiaratively elongate; the head small, 

 rather narrow, depressed anteriorly; the snout rather narrow and moder- 

 ately rounded. Eye moderate, placed well above mouth, its length 5^ in 

 head. Interorbital space flat and smooth, 2\ in head; snout 3^; breadth 

 of mouth 2. Mouth rather large, with thickish lips; tc^eth villiform; 

 vomerine bands moderate, conHuent with each other and with the much 

 larger ovate j)alatine bands, a slight constriction or furrow making the 

 divisions; palatine bands each with a backward prolongation; premax- 

 illary band moderate ; barbels very short ; maxillary barbel scarcely or 

 not reaching to base of pectoral ; outer mental barbel scarcely past gill 

 opening below; inner shorter than snout. Dorsal shield short, anteri- 

 orly truncate, not keeled, the length on the median line about \ of 1 of 

 its halves. Occipital process subtriangular, rather narrow, truncate 



