50 ACANTIIOPTEETGII. 



5. Ceiitropoiiiiis viridis. 



Centropomiis rirhlis, Lockiugton, Proc. Calif. Ac. Sci. viii. 1877, p. 110 ' ; Jord. & Everm. Bull. 



U.S. Nat. INIus. xlvii. 1896. p. 1118 \ 

 Ct'iilropomus viideciriialis (|>art.), Gilb. & Starks, Mem. Calif. Ac. Sci. iv. 1904, p. 89'. 



Depth of body 4.]-4^ in the lengtli, length of head 2;i-3. Snout 2-2| as long as eye, the diameter of which 

 is S in tlie length of head, iuterorbital width "l-^l. Maxillaiy extending beyond middle of eye, its 

 greatest widtli J the diameter of eye. Pra>orl)ital weakly serrated; prieoperouliim acutely serrated, the 

 serra3 enlarged at the angle ; 1 or 2 feeble spines at angle of prEeopercular ridge. Opercular flap not 

 reaching tlie vertical from origin ol' dorsal. S or 9 well-developed gill-rakers and a few rudiments on the 

 lower part of anterior arch. G5-70 scales in a longitudinal series, 8 or 8i between middle of second 

 dorsal and lateral line. Dorsal VIII, I 9 ; tliird spine longest, i the length of head. Anal III ; 

 second and third sjiines subequal in lengili, nearly i the length of the fish. Pectoral i 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 ])eduncle - as long as deep. Silvery or golden, back greenish; lateral 

 line blackish : spinous dorsal dusky. 



Ilah. Pacific Coasts of Tropical America : 



Lower California, Asuncion I. k — Mazatlan - ; Panama ~ ^. 



Here described from two specimens, 350 and 380 mm. in total length, from Panama 

 and Mazatlan. 



As in its Atlantic representative, C. iindecimrdis, the air-bladder has a pair of anterior 

 appendages. From C. irndecimalis, with which it has beeir confused, this species is 

 seen to differ, when specimens of the same size are compared, in the somewhat smaller 

 eye, broader intcrorbital region, broader maxillary, shorter anal spines, and more 

 anteriorly placed vent. Moreover, the two specimens here described agree in having 

 9 branched rays in the dorsal fin, whilst all I have seen of C. irndecimalis have 10. 



The principal differences are shown by the following measurements (in millimetres) 

 of the two specimens of C. viridis and the two of C. undecimalis which come nearest 

 to them in size : — 



C. virirhs 



Lcngtli, to base of caudal 3l'0 



Iuterorbital width 14 



Length of second anal spine 4.5 



Distance from base of ventral spine to vent 70 



,, ,, vent to origin of anal 40 



6. Ceiitropomus nigrescens. 



CenlropoiuHS viyrvscens, Gihitli. Proc. Zool. Soc. 18GI, p. 144', and Trans. Zool. Soc. vi. 1868 

 p. 407 '; Vaill. & Hoc. ]\Ii,ss. Sci. Mex., Poiss. p. ,20, t. 1 bis, tig. 1 (1874) ' ; Boulcii"-. Cat. 

 Pisl]. 1. p. 368 (189.j) '; Jord. & Evcrm. Bull. U.S. Nat. Mus. xlvii. 1896, p. 1119"'; Gilb 

 & Starks, Mem. Calif. Ac. Sci. iv. 1904, p. 90". 



('ciilropoiiias iiruleciina/ls (part.), Boulciig. t. c. p. 367'. 



Dcplli of l)ody 4 m the length, lejigtlj of liead 2:j-2,i. Snout l.;-l J as long as eye, tlio diameter of which is 

 .5-7 ill the length of head ; inteiorbital width 7-71 in flic length of head. Jlaxillary extending to below 



