246 BULLETIN 189, UNITED STATES NATIONAL MUSEUM 



Range. — Known from only one specimen from Capon, vicinity of 



Tumbes, Peru. 



Genus ISACIA Jordan and Fesler, 1893 



Body elongate, moderately compressed; head rather pointed; 

 mouth moderately small, oblique; maxillary reaching about to front 

 of eye; scales moderately small, firm, ctenoid, forming a low sheath 

 on base of soft part of dorsal and anal; gill rakers well developed, about 

 20 to 25 on lower limb of first arch; dorsal fin rather deeply notched, 

 with 13 spines and about an equal number of soft rays; caudal with a 

 shallow fork; anal with three rather weak graduated spines and about 

 12 or 13 soft rays. 



A single species is known, which inhabits the coasts of Peru and 

 Chile. 



ISACIA CONCEPTIONIS (Cnvier and Valenciennes) 



Cabinsa 

 Figure 54 



Pristipoma conceptionis Cuvier and Valenciennes, 1830, p. 268, Concepci6n, 

 Chile (original description). 



Isacia conceptionis Abbott, 1899, p. 350, Callao, Peru (generic relations discussed; 

 diagnosis ; range) . — Steindachner, 1902, p. 116, Callao, Peru (description). — 

 Starks, 1906, p. 789, fig. 9, Callao, Peru (diagnosis).- — ^Evermann and 

 Radcliffe, 1917, p. 89, Santa Rosa Island, Independencia Bay; MoUendo; 

 Guanape North Island; region of Pisco; Callao; and Lobos de Afuera, Peru 

 (discussion of the identity of this species and I. venusia; description). — 

 Nichols and Murphy, 1922, p. 509, Chincha Islands, and Pescadores Islands, 

 off Ancon. — Fowler, 1940b, p. 772, fig. 54, "Peru" and Valparaiso, Chile. 



Isacia venusta Starks, 1906, p. 789, fig. 10, Callao, Peru (original description; 

 compared with /. conceptionis). 



Head 2.9 to 3.3; depth 2.8 to 3.4; D. XIII, 13 to 15; A. Ill, 12 or 13; 

 P. 18 or 19; scales 70 to 80; vertebrae 27 (two specimens dissected). 



Body moderately compressed, its greatest thickness about half its 

 depth; back moderately elevated; profile over head gently convex; 

 caudal peduncle rather slender, 3.2 to 3.8 in head; snout pointed, 3.2 to 

 4.0; eye 3.3 to 5.2; interorbital 3.25 to 5.0; mouth moderate, oblique; 

 lower jaw moderately projecting; maxillary generally extending under 

 anterior margin of eye, 3.2 to 3.9 in head; teeth in each jaw in a narrow 

 band, the outer ones scarcely enlarged; vertical limb of preopercle 

 straight to somewhat concave, finely denticulate, horizontal limb un- 

 armed; gUl rakers fairly short, those at angle about half length of eye, 

 20 to 24 more or less developed on lower and 10 to 14 on upper limb of 

 first arch; scales rather firm, ctenoid, reduced on head, missing on 

 snout, extending more or less on caudal, ventral, and pectoral fins, 

 rows of scales above lateral line not parallel with it, about 9 or 10 com- 

 plete rows between lateral line and origin of dorsal, 6 (occasionally 5) 

 rows on caudal peduncle between lateral line and median dorsal row, 

 and 7 (occasionally 6) below lateral line and median ventral row; 

 dorsal rather deeply notched, the fourth spine generally longest, much 



