294 BULLETIN 189, UNITED STATES NATIONAL MUSEUM 



gives 85 scales in lateral line. Other characters mentioned in the 

 original description are in fair agreement with the specimen at hand. 

 Range. — Known only from Peru. 



Genus OPHIOSCION Gill, 1863 



Body elongate, more or less compressed ; head rather low and short, 

 not especially broad between the eyes, the bones rather firm (not 

 notably cavernous); snout usually projecting more or less beyond 

 premaxillaries ; slits and pores about the mouth well developed; 

 mouth generally nearly horizontal; teeth in each jaw in a band; 

 preopercular margin serrate; gill rakers usually quite short; scales 

 ctenoid, extending more or less at least on second dorsal, caudal, and 

 anal; caudal fin lanceolate to double truncate; first dorsal generally 

 with 10 or 11 spines; second dorsal with about 20 to 30 soft rays; 

 anal with 2 spines and about 7 to 9 soft rays. 



This genus heretofore has not been recorded from Peru. In addi- 

 tion to the new species described, the collection contains a juvenile, 

 45 mm. long, seined in Chilca Bay, which apparently is not identifiable 

 with any known species. However, because of its small size and not 

 especially good condition it will be mentioned only briefly. It differs 

 from 0. obscurus herein described in having a lower and broader head; 

 a shorter snout, which scarcely projects beyond the premaxillaries; 

 the body and especially the caudal peduncle are slenderer; the second 

 dorsal spine is no stronger than the third; and the second dorsal is a 

 little shorter, having only 23 rays. 



It seems to be worth mentioning that in 54 specimens, of 8 species, 

 mostly from the coasts of Panama, the number of rays in the anal fin 

 is absolutely constant within a species. Therefore, the differences of 

 a single ray in this fin apparently may be regarded as of specific 

 importance. 



OPHIOSCION OBSCURUS, new species 



Figure 63 



Head 3.5, 3.3; depth 3.3, 3.0; D. X-I, 26, X-I, 25; A. II, 7, II, 7; 



P. 17, 18; scales 57, 56. 



Body elongate, compressed, its greatest thickness little more than 

 half its depth; back thin, elevated; dorsal outline gently convex in 

 advance of dorsal fins; ventral outline nearly straight and horizontal; 

 head compressed; caudal peduncle rather strongly compressed, 2.6, 

 2.6 in head; snout moderately long, blunt, projecting well in advance 

 of premaxillaries, 3.9, 4.0 in head; eye 3.5, 3.4; interorbital convex, 

 4.0, 3.9; mouth inferior, nearly horizontal; lower jaw included; maxil- 

 lary reaching vertical from posterior margin of pupil, 2.7, 2.6 in head; 

 teeth in each jaw in a band, the outer series in upper jaw somewhat 

 enlarged; preopercular margin serrate, the serrae increasing in size 

 gradually toward the angle, the spine at angle largest, directed 

 slightly downward; gill rakers well developed, those at angle about 



