THE SHORE FISHES OF PERU 105 



Head 2.5 to 3.1; depth 3.3 to 4.3; D. 14 to 16; A. 21 to 24; P. 15; 

 scales 42 to 45; vertebrae 41 or 42 (three specimens dissected). 



Body strongly compressed, rather deep, increasing proportionately 

 with age, its greatest thickness exceeding depth of the slender caudal 

 peduncle, ventral outline much more strongly convex than the dorsal; 

 head long, especially posterior to eye, increasing with age, its depth 

 at joint of mandible about equal to postorbital part of head in very 

 young, much shorter than that part of head in large specimens; snout 

 notably shorter than eye, 7.5 to 10 in head; eye wholly in anterior 

 third of head in adults, 5.0 to 6.0; postorbital part of head 3.7 to 4.7 

 in length; maxillary rounded distally, not quite reaching joint of 

 mandible, 1.75 to 1.85 in head; mandible 1.75 to 1.85; cheek very 

 long and narrow, much longer than snout and eye in adults ; gill rakers 

 long, slender, increasing greatly in number with age, about 25 on 

 lower limb of first arch in specimens about 50 mm. long, about 60 in 

 specimens 140 mm. in length; scales thin, moderately adherent, with 

 slightly uneven edges; dorsal fin rather low, the longest rays not nearly 

 reaching tip of last one if deflexed, origin of fin about equidistant from 

 anterior margin of eye and base of caudal; anal moderately long and 

 low, its origin under posterior half of base of dorsal, its base 4.6 to 5.0 

 in length; ventral reaching somewhat more than halfway to origin of 

 anal, inserted a little nearer origin of anal than base of pectoral; 

 pectoral generally failing to reach base of ventral by diameter of pupil, 

 2.15 to 2.6 in head, 6.2 to 7.2 in length; axillary scale of pectoral about 

 three-fourths length of fin, 3.05 to 3.9 in head. 



Color bluish gray above; sides silvery, especially sides of head; 

 young with a silvery lateral band, becoming indistinct and disappear- 

 ing at a length of about 85 to 100 mm. ; back with dusky punctulations, 

 these continued on caudal fin. 



This species is represented in the collection made by the Mission by 

 three small specimens, 41 to 55 mm. long, dredged off the mouth of 

 the Piura River in Sechura Bay. The description is based on these 

 specimens, and larger ones from Panama Bay. 



Range. — Gulf of California to northern Peru. 



Family MAUROLICIDAE 



Body moderately elongate, compressed; margin of upper jaw formed 

 by maxillaries and premaxillaries, each provided with teeth; barbels 

 wanting; gill openings wide, the first arch extending forward to sym- 

 physis of lower jaw; pseudobranchiae present; air bladder wanting; 

 series of photophores extending along lower part of side of head, body, 

 and tail; scales at least sometimes present; dorsal fin single, with soft 

 rays only; adipose fin small or rudimentary, 



A sinsrle genus is known from off the coast of Peru. 



