FAM. XVIII. CENTROPOMID.E. FAM. XIX. H^EMULID^E. 199 



a strong supplemental bone; preopercle with a double ridge, the 

 posterior margin strongly serrate ; opercle without true spines ; scales 

 ctenoid; lateral line conspicuous; dorsal fins well separated, the first 

 with 8 spines; anal spines 3, the second strong, the third long and 

 slender; these fins moving in scaly sheathes; air bladder well devel- 

 oped; branchiostegals 7. Species all American, one species found in 

 the rivers of southeastern Mexico far above tide-water. 



78. Centropomus Lace"pede. 



ROBALOS. 



Centropomus Lacepede, Hist. Nat. Poiss., iv, 248, 1802. (Type re- 

 stricted by Cuvier & Valenciennes to Scicena undecemalis Bloch). 

 Characters of the genus are included in the description of the family. 



188. Centropomus mexicanus Bocourt. ROBALO. 



Centropomus mexicanus Bocourt, Ann. Sci. Nat. Paris, 1868, 90; 

 Gulf of Mexico: Vaillant & Bocourt, Miss. Sci. Mex., 1875, 23, 

 pi. i, fig. 2: Jordan & Evermann, Bull. 47, U. S. Nat. Mus., 

 1896, 1121. 



Both coasts of Mexico, ascending rivers to a considerable distance 

 above tide-water. (San Francisco; Boca del Rio; El Hule; Perez.) 



Head 2^; depth 4 to 4^; D. vm-i, 10; A. in, 6; scales 11-69 

 to 72-16. Body elongate, moderately compressed; mouth large, maxil- 

 lary reaching nearly to posterior margin of pupil ; preopercle with 

 sharp teeth on its posterior limb, the two at the angle larger than 

 the others ; 2 spines at angle of anterior limb ; diameter of eye 5 % in 

 head; third dorsal spine the longest, 2 in head; second anal spine 

 very strong, if in head; lateral line well developed; caudal fin forked. 



Color olivaceous, lighter below; lateral line blackish; tips of dorsal 

 and caudal blackish. Length 12 inches or more. 



Family XIX. Hfemulidse. 



THE GRUNTERS. 



Body oblong, more or less elevated, covered with moderate sized 

 scales, usually ctenoid; lateral line concurrent with the back, usually 

 not extending on caudal fin ; head large ; no suborbital stay ; premaxil- 

 laries protractile; maxillary without supplemental bone, for the most 

 of its length slipping under edge of preorbital; preorbital usually 

 broad ; no barbels ; no teeth on vomer or palatines ; ventral fin thoracic, 

 its rays 1.5; pyloric ccecae few; vertebra? usually 10+14 = 24; alimen- 

 tary canal short. Mostly shore fishes, a few entering fresh water. 



