104 BULLETIN 189, UNITED STATES NATIONAL MUSEUM 



striae; dorsal fin with a rather deeply concave margin, the longest 

 rays nearly or quite reaching tip of last ray if deflexed, origin of fin 

 usually nearer base of caudal than tip of snout, rather variable; anal 

 moderately small, its origin variable, sometimes just behind base of 

 last ray of dorsal, more usually under posterior rays of dorsal, its base 

 4.2 to 4.6 in length; ventral reaching fully halfway to origin of anal, 

 inserted about equidistant from base of pectoral and origin of anal; 

 pectoral rather variable in length, sometimes reaching base of ventral, 

 more usually falling short of this point, 1.6 to 1.9 in head, 5.3 to 6.3 

 in length; axillary scale broad at base, about two-thirds length of fin, 

 2.5 to 3.4 in head. 



Color of preserved specimens, silvery where scales remain; sides 

 of head bright silvery; side with a bright silvery band, becoming in- 

 definite in specimens about 115 mm. long, and disappearing in large 

 examples; back with dusky punctulations, forming a dark median 

 band in the smaller specimens; dorsal and caudal with dark points, 

 the caudal often with dark tips and margin; other fins pale; the smaller 

 specimens with dark dots along base of anal. 



The collection made by the Mission contains 14 small specimens from 

 the Gulf of Guayaquil off Puerto Pizarro, taken with a dredge. Twelve 

 specimens from other collections, all from Callao, have also been used 

 in preparing the foregoing description, which is based on specimens 

 48 to 140 mm. long. 



This species is close to A. naso, as shown in the account of the last- 

 mentioned species. 



Range. — Gulf of Guayaquil, off Puerto Pizarro to Chincha Island, 

 Peru. 



Genus CETENGRAULIS Giinther, 1868 



Body deep in adults, strongly compressed; maxillary short, rounded 

 distally, reaching near joint of mandible; teeth minute; gill rakers 

 long, slender, increasing greatly in number with age; gill covers con- 

 nected across the isthmus by a thin transparent membrane, easily 

 torn, much narrower in the young than in adults; ventral fin inserted 

 under or a little in advance of origin of dorsal; a silvery lateral band 

 present in the young. 



A single species comes within the scope of the present v>^ork. 



CETENGRAULIS MYSTICETU9 (GUnther) 



EngrauUs mysticetus Gunther, 1866, p. 604, Panama Bay (original description). 



Stolephorus opercularis Jordan and Gilbert, 1882a, p. 275, Punta San Felipe, 

 Gulf of California (original description). 



Cetengraiilis eng^jmen Gilbert and Pierson, in Jordan and Evermann, 1898, 

 p. 2815, Panama Bay (original description, based on young). 



CetengrauUs mysticetus Meek and Hildebrand, 1923, p. 212, Panama Bay 

 (synonym3%- description; range). — Hildebrand, 1943a, p. 157, fig. 72 (syn- 

 onymy; description; compared with C. edentulus; range). 



