THE SHORE FISHES OF PERU 259 



KEY TO THE GENERA 



a. Lower jaw with a single short stout barbel at tip, or with a row of small slender 

 barbels along inner edge of dentary bones. 

 b. Lower jaw with a single barbel at tip. 



c. Anal with a single weak spine; margin of preopercle without bony serrae. 



Menticirrhus (p. 259) 

 cc. Anal with 2 spines, the second one rather large; margin of preopercle finely 



serrate Umbrina (p. 266) 



bb. Lower jaw with a row of slender barbels along inner edge of dentary bones, 

 forming a tuft at tip; anal with 2 rather small spines. 



Paralonchurus (p. 268) 

 aa. Lower jaw without barbels. 



d. Either the upper or the lower jaw with a pair of canines anteriorly. 



e. Upper jaw anteriorly with a pair of large recurved canines; mouth very 



large; lower jaw projecting Cynoscion (p. 273) 



ee. Lower jaw with a pair of canines near tip; mouth only moderately large, 



terminal; lower jaw generally not projecting Odontoscion (p. 280) 



dd. Anterior part of jaws without enlarged pairs of canines. 



/. Bones of head rather firm, not especially spongy to the touch; head gener- 

 ally rather narrow, compressed. 

 g. Mouth usually more or less horizontal, terminal or more frequently in- 

 ferior; slits and pores about the mouth well developed; gill rakers 

 short, about 6 to 15 on lower limb of first arch. 

 h. Margin of preopercle unarmed, or rarely with a few feeble spines at 



angle in small specimens Sciaena (p. 282) 



hh. Margin of preopercle strongly serrate at all ages. Ophioscion (p. 294) 

 gg. Mouth somewhat oblique to nearly vertical; lower jaw sometimes project- 

 ing; slits and pores about the mouth undeveloped; gill rakers long and 

 slender, about 15 to 25 on lower limb of first arch. 

 i. Mouth strongly oblique to nearly vertical; lower jaw projecting; mar- 

 gin of preopercle without bony serrae Larimus (p. 296) 



ii. Mouth moderately oblique to nearly horizontal; lower jaw generally 

 not projecting; margin of preopercle strongly serrate. 



Bairdiella (p. 300) 

 ff. Bones of head cavernous, often quite spongy to the touch; head generally 

 low and broad. 

 j. Margin of preopercle armed with 1 to about 8 bony serrae; eye of moder- 

 ate size (about 3.5 to 5.5 in head) ; scales rather large (about 45 to 55 in 



lateral series), ctenoid Stellifer (p. 301) 



jj. Margin of preopercle unarmed; eye very small (about 8 to 10 in head); 

 scales very small (about 80 to 120 in lateral series) , mostly cycloid. 



Nebris (p. 309) 



Genus MENTICIRRHUS Gill, 1861 



Body rather elongate, little compressed; head long, rather low; 

 snout subcorneal, projectmg beyond premaxillaries, with slits and 

 pores above premaxillaries; mouth horizontal, inferior; lower jaw 

 with a single, short, thickish barbel at tip; teeth in each jaw in a more 

 or less definite band, the outer ones in upper usually somewhat en- 

 larged; preopercle with a membranous margin; gill rakers short, tuber- 

 cular or obsolete; dorsal with about 10 to 13 flexible spines, and about 



