2758 Bulletin //, United States National Museum. 



breadth about equal to the diameter of the eye, and ^ its length, a short 

 groove extending backward from its obtuse tip; sides of fontanel bony 

 and granulated for its whole length, the granules extending forward to 

 opposite nostrils. Dorsal spine strong, If in head, moderatel^^ com- 

 pressed; pectoral spine 1* in head. Axillary pore obsolete. Humeral 

 process coarse, granular, broad, nearly I length of iiectoral spine ; base 

 of adipose fiu scarcely \ length of anal, its posterior margin little free; 

 caudal deeply lunate, small, its ui)per lobe slightly the longer aud nar- 

 rower, \\ in liead; A^entrals not quite reaching aual; veut much nearer 

 base of ventrals than aual. Dark brown, with strong bronze luster 

 above, white below; dorsal dusky, especially above ; pectorals blackish; 

 anal dark; caudal rather pale; ventrals usually dark toward the tip, 

 their inner side i^ale; maxillary barbel dusky ; mental barbels pale. This 

 species is not rare along the Pacific coast of tropical America, speci- 

 mens having been observed at Mazatlan, Punta Arenas, aud Panama. 



Sciades troscheli, Gill, Proc. Ac. Nat. Sci. Phila. 1863, 171, Panama. (Coll. Cajit. Dow.) 

 Arins brandtii, Jordan & Gilbert, Bull. U. S. Fi.sh Comm., ii, 1882, 39; description from 

 28230, U. S. Nat. Mus., 24 iiiclies in length. 



The following is the original description of Sciades troscheli, Gill : 

 "Dorsal I, 7; anal 16; caudal 11, I, 6; 7, I, 11. The greatest height is 

 contained about 4i times in the length to the base of the caudal tin, and 

 5i times iu the total. The caudal peduncle, behind the anal, equals the 

 interval between the snout and the eye, and its least height that between 

 the center of the anterior nostril and the eye. The head in front and on 

 the sides is smooth, and a smooth, oblong, triangular area extends nearly 

 to the vertical from the upper angle of the in-eoperculum; a triangular 

 area on each side is incurved externally to the narrow anterior extremity, 

 and covered with white pisiform grauulations. The dorsal buckler is a 

 pentagon, with a semicircular excavation l>ehind and with its surface 

 rugose. The head enters 3 times in the length before the end of the anal 

 fin and more than 4 times in the total; its width ei^uals the interval 

 between the snout and upper angle of preoperculum, and the interocular 

 area equals ^ the head's length. The eye is elliptical, and its diameter 

 is contained 6| times in the head's length. The distance of the posterior 

 nostril from it ecinals a diameter. The maxillary barbels extend to about 

 the middle of the pectoral; the outer mental to its base, and the inner 

 mental are f as long as the outer. There are 3 villiform patches on 

 the palate which are almost contiguous, aud together descrilie an arch in 

 front; the median patch is small, rather transverse, and widest toward 

 the front; the outer are oblong, sulttriangular. The band of the upper 

 jaw is nearly uniform and quite wide; the lower, interrupted at the 

 symphysis, is nearly I as wide as the upper, aud is narrowed toward 

 its ends. The dorsal spine enters 11 times in the head's length; has iu 

 front, first, minute teeth pointed downward, and then a row of small 

 pisiform tubercles ; teeth pointed downward on its hinder border. The 

 first ray is little higher than the spine. The anal commences at a dis- 

 tance from the suout 3f times as great as that from the base of the caudal 



