50 ACANTHOPTERYGII. 
5. Centropomus viridis. 
Centropomus viridis, Lockington, Proc. Calif. Ac. Sci. viii. 1877, p.110'; Jord. & Everm. Bull. 
U.S. Nat. Mus. xlvii. 1896, p. 1118 °. 
Centropomus undecimalis (part.), Gilb. & Starks, Mem. Calif. Ac. Sci. iv. 1904, p. 89°. 
Depth of body 4j-43 in the length, length of head 24-3. Snout 2-2} as long as eye, the diameter of which 
is 8 in the length of head, interorbital width 7-74. Maxillary extending beyond middle of eye, its 
greatest width + the diameter of eye. Preeorbital weakly serrated ; preeoperculum acutely serrated, the 
serre enlarged at the angle; 1 or 2 feeble spines at angle of preopercular ridge. Opercular flap not 
reaching the vertical from origin of dorsal. 8 or 9 well-developed gill-rakers and a few rudiments on the 
lower part of anterior arch. 65-70 scales in a longitudinal series, 8 or 84 between middle of second 
dorsal and lateral line. Dorsal VIII, 19; third spine longest, 4 the length of head. Anal IIT 6; 
second and third spines subequal in length, nearly } the length of the fish. Pectoral 3 the length of 
head. Ventrals not reaching vent, which is situated at about 3 of the distance from base of ventral 
spine to origin of anal. Caudal peduncle 2 as long as deep. Silvery or golden, back greenish; lateral 
line blackish; spinous dorsal dusky. 
fab. Pacific Coasts of Tropical America: 
Lower California, Asuncion I. !.—Mazatlan?; Panama? 3. 
Here described from two specimens, 350 and 580 mm. in total length, from Panama 
and Mazatlan. 
As in its Atlantic representative, C. undecimaiis, the air-bladder has a pair of anterior 
appendages. From C. wndecimalis, with which it has been confused, this species is 
seen to differ, when specimens of the same size are compared, in the somewhat smaller 
eye, broader interorbital 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. undecimalis 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. wndecimalis which come nearest 
to them in size :— 
C.” viridis. C. undecimalis. 
o_* — oT TS 
Length, to base of caudal .... 2.0... eee ee eee 320 345 295 330 
Interorbital width 2.0... 0.0... cee eee ee eee ee 14 17 12 12 
Length of second anal spine .... 2... 0. Le cee ee eee 45 49 51 54 
Distance from base of ventral spine to vent ............ 70 80 70 88 
» 5, vent to origin of anal............ 00.005 40 45 30 32 
6. Centropomus nigrescens. 
Centropomus nigrescens, Giinth. Proc. Zool. Soc. 1864, p. 144°, and Trans. Zool. Soc. vi. 1868, 
p. 407°; Vaill. & Boc. Miss. Sci. Mex., Poiss. p. 20, t. 1 bis, fig. 1 (1874) °; Bouleng. Cat. 
Fish, 1. p. 868 (1895) *; Jord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1896, p. 1119°; Gibb. 
& Starks, Mem. Calif. Ac. Sci. iv. 1904, p. 90°. 
Centropomus undecimalis (part.), Bouleng. t. c. p. 367". 
Depth of body 4 in the length, length of head 23-24. Snout 13-12 as long as eye, the diameter of which is 
5-7 in the length of head ; interorbital width 7-7} in the length of head. Maxillary extending to below 
