270 
BLTLL.ETIN OF THE BUREAU OF FISHERIES 
Several large individuals, ranging upward to 715 millimeters in length, were 
taken with dynamite in the Rio Lempa at San Marcos. Only one specimen, 475 
millimeters long, was preserved, which, together with notes and measurements made 
in the field on still larger specimens, serves as the basis for the above description. 
The "Rovalo" was reported by local inhabitants from several localities and 
streams in El Salvador, but, as already stated, it was taken only in one locality. 
Native fishermen at Suchitoto claimed that "Rovalo" exceeding a meter in length 
are occasionally taken there in the Rio Lempa. It is probable that this species and 
possibly several others of this genus ascend the river to and beyond that locality, 
as most of the representatives ascend fresh-water streams freely. 
This species is known from Lower California to Ecuador. In El Salvador it 
was taken in the Rio Lempa at vSan Marcos. 
15. Centropomus robalito Jordan and Gilbert 
RoBALo; Rovalo 
Centropomus armatus Oiinther (not Gill) Trans., Zoiil. Soc, London, 1868, 408. 
Centropomus robalito Jordan and Gilbert, Proc, U. S. Nat. Mus., IV, 1881 (1882), 462 (Mazatlan; Acapulco); Jordan and Ever- 
mann, Bull., U. S. Nat. Mus., XLVII, 1896, 1123. 
Head 3 to 3.1; depth 3.25 to 3.4; D. VIII-I, 10; A. Ill, 6; scales 52 to 54. 
Body moderately elongate, compressed; back elevated; head long, rather flat 
above; snout long and broad, its length 2.75 to 3 in head; eye 4 to 4.15; interorbital 
4.75 to 6.8; mouth large, a little oblique, lower jaw strongly projecting; maxillary 
reaching nearly opposite middle of eye, 2.35 to 2.45 in head; preorbital with small 
serrations; preopercle strongly serrate, 2 serrae at angle notably enlarged; pre- 
opercular ridge with 2 spines at angle; gill rakers slender, rather numerous, 16 or 
17 on lower limb of first arch; scales moderate, ctenoid, 5 or 53>^ rows between middle 
of second dorsal and lateral line, reduced in advance of dorsal, about 14 rows cross- 
ing the back anterior to spinous dorsal, small scales extending on base of second 
dorsal, caudal, and anal; origin of first dorsal scarcely an eye's diameter behind 
base of pectorals, the third spine about equal in length to the fourth but not reach- 
ing beyond it when defiexed, 1.55 to 1.65 in head; origin of second dorsal about 
equidistant from preopercular margin and base of caudal; caudal fin forked, both 
lobes acute; origin of anal fin slightly posterior to middle of base of second dorsal, 
the second spine much enlarged, reaching somewhat beyond base of caudal when 
defiexed, its length 1.15 in head; ventral fins inserted slightly behind base of pec- 
torals, reaching to or a little beyond vent; pectorals not quite reaching tips of 
ventrals, 1.35 to 1.6 in head. 
Color bluish gray above, silvery below; lateral line not in a black streak; fins 
all more or less dusky; spinous dorsal usually with more or less black on interradial 
membranes; membrane between second and third anal spine, with black next to 
the third spine. 
Several small specimens, ranging in length from 120 to 140 millimeters, were 
seined in the Rio Lempa at San Marcos in strictly fresh water and well beyond the 
infiuence of tides. One small specimen of this species was taken in an estuary at 
Triunfo. 
