CEXTEOPOMUS. 51 



middle of eye or beyond, its greatest width. 4— j tlic diameter of eye. Prreorbital -weakly serrated ; prno- 

 operculum acutely serrated, the serrte enlarged at the angle ; 1 or 2 feeble spines at angle of pneoperoular 

 ridge. Opercular flap not reaching the vertical from origin of dorsal. 8 or 9 well-developed gill-raliors 

 and a few rudiments on the lower part of anterior arch. 73-80 scales in a longitudinal series, 9 or in 

 between middle of second dorsal and lateral line. Dorsal VIII, I 10 ; third or fourth spine longest, 

 i the length of head. Anal III 6 ; second and third spines subequal in length, i- 1 the lengtli of tlic 

 fish. Pectoral 4 or a little more than j the length of head. Ventrals not reaching vent, which is 

 situated at about f of the distance from base of ventral spine to origin of anal. Caudal peduncle 1 j-- 

 as long as deep. Silvery, back brownish ; lateral line blackish ; spinous dorsal usually blackish : other 

 fins usually more or less dusky. 



Hah. Pacific Coasts of Tropical America, entering rivers: 



Mexico, Mazatlan'*^^ p^^^^ Presidio "^ (i^orr«-), Rio Mascota' {BuUer); Guate- 

 mala, Chiapam ^ " [Salvin) ; Panama ^ '^. 



Here described from tliree specimens, 150-300 mm. in total length, from the Eio 

 Presidio, the Eio Mascota, and Chiapam. 



This species is very closely allied to C. virid/'s, but the anterior processes of the air- 

 bladder are wanting, whilst the third dorsal spine is shorter, the scales are somewhat 

 smaller, and the vent is placed a little further back. There appear to be constantly 

 10 branched rays in the second dorsal fin. 



7. Centropomus robalito. 



Centropomus ariiiatus (non Gill), Giinth. Trans. Zool. Soc. vi. 18G8, p, 408'. 



Centropomus rohtiUto, Jord. & Gilb. Proc. U.S. Nat. Mas. iv. 1882;, p. 4G2"; Jord, & Everm. Bull. 



U.S. Nat. Mus. xlvii. 189G, p. 1123 '; Gilb. & Starks, Mem. Calif. Ac. Sti. iv. 1904., p. 94, 



t. 13. fig. 2.5 '. 

 Centropomus ensifents (part.), Boiileng. Cat. Fish. i. p. 369 (1895) '. 



Depth of body 3j-3| in the length, length of head 2|-2-?-. Snout lg-2 as long as eye, the diameter of which 

 is 6-7j in the length of head ; interorbital width 8 in the length of head. Maxillary extending to below 

 middle of eye, or nearly, its greatest width ji— i the diameter of eye. Pragorbital acutely serrated 

 posteriorly ; prseopercnlum acutely serrated, with 1 or 2 enlarged serriB at the angle ; praeopercular ridge 

 with 1 or 2 spines at the angle. Opercular flap extending a little beyond the vertical from origin of 

 dorsal. 17-19 gill-rakers, including 2 or 3 rudiments, on the lower part of auterior arch. 48-54 scales 

 in a longitudinal series, 5-U,^ between middle of second dorsal and lateral line. Dorsal VIII, 1 10; 

 spines of moderate strength, the third the lougest, about h tlie length of head. Anal III <J ; third spine 

 |— I as long as second, which is from \ to a little more ttum j the length of Uie fish. Pectoral 4 as long 

 as head. Ventrals extending about to the vent, which is situated at i of the distance from base of 

 ventral spine to origin of anal. Caudal peduncle 1-^-1;; as long as deep. Silvery or golden, back 

 brownish ; lateral line not blackish ; spinous dorsal and membrane between second and third anal spines 

 usually blackish. 



Hah. Pacific Coasts of Tropical America, entering rivers : 



Mexico, Rio Presidio^ {Forrer), Mazatlan - 2, Acapttlco ^ s ; Guatemala, Chia- 

 pam 1 ■■' [Salvin) ; Panama ^ *. 



Here described from nine specimens, ISO- 300 ram. in total length, from Panama, 

 Chiapam, Mazatlan, and the Rio Presidio. 



H2 



