THE SHORE FISHES OF PERU 435 



POLYNEMUS OPERCULARIS (Gill) 



Barbudo 



Trichidion opercularis Gill, 1863c, p. 168, Cape San Lucas, Baja Calif ornia (original 



description). 

 Polynemus opercularis Meek and Hildebrand, 1923, p. 292, Panama City 



(synonymy; description; range). 



Head 3.5; depth 4.25; D. VIII-I, 12; A. Ill, 14; P. 15; scales 67. 



Body moderately compressed, its depth at origin of second dorsal 

 fully twice as great as its thickness; caudal peduncle rather strongly 

 compressed, its depth 2.5 in head; head compressed; snout projecting 

 about two-thirds its length beyond tip of mandible, 5.3 in head; eye 

 5.0; interorbital convex, 4.3; mouth large, nearly horizontal; maxillary 

 broad, convex posteriorly, 1.7 in head; teeth all very short, pointed, 

 directed inward, in a broad band in each jaw, band interrupted on 

 median line in each jaw, largely exposed with mouth closed, a broad 

 patch on vomer, and a posteriorly pointed band of palatine-pterygoid 

 teeth; preopercle with a projectmg membranous flap at lower posterior 

 angle, the margin above flap strongly serrate; gill rakers rather long, 

 21 on lower and 16 on upper limb of first arch; lateral line nearly 

 straight, extending somewhat on caudal fin; scales thin, pectinate, the 

 jointed ridges of the spines extending far on surface, scales extending 

 forward on head to tip of snout, small ones on maxillary and lower 

 jaw, densely covermg second dorsal, caudal and anal, some scales 

 present on other fins also; dorsal fins far apart, the origin of the first a 

 little behind base of pectoral and rather nearer eye than origin of 

 second dorsal, the third and fourth spines of about equal length, failing 

 to reach origin of second dorsal by diameter of eye if deflexed, 5.5 in 

 length ; second dorsal somewhat elevated anteriorly, and the last ray 

 a little produced; anal similar to second dorsal, its origin about under 

 middle of second dorsal, its base 5.9 in length; ventral much smaller 

 than pectoral, inserted a little nearer origin of anal than tip of mandible ; 

 pectoral long pointed, 4.7 in length, 1.3 in head; pectoral filaments 9, 

 in part longer than head, reaching nearly to vent. 



Color gray above, pale below; an obscure opercular spot present; 

 dorsal fins and caudal dusky gray; other fins pale. 



The foregoing description is based on the only specimen secured by 

 the Mission. This fish, which is 405 mm. (306 mm. to base of caudal) 

 long, was taken in the Gulf of Guayaquil, off Puerto Pizarro. It was 

 compared with 3 smaller specimens, 140, 200, and 255 mm. long, from 

 Panama. With these it agrees fairly well, except that the gill rakers 

 are a little less numerous in the Panama fish, which all have 18 on the 

 lower and 14 on the upper limb of the first arch. Their ventral fins 

 reach to or beyond the vent, and their pectoral filaments reach to or 

 beyond origin of anal. That the last-mentioned characters vary with 



