THE FISHES OF PORTO 1UCO. 
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Family XXXIX. CENTROPOMIDtE. The Robalos. 
This family is defined thus by Professor Gill (Proc. U. S. N. M. 1882, 484) : 
“Typical acanthopterygians with the postorbital portion of the skull longer than theoculo-rostral; 
the parietals behind the constriction continuous with the epiotics and transverse lam hue arising from 
the supraoccipital crest, the three together forming a well differentiated posterior oblong pentagonal or 
hastiform area; the re-entering parietal sinus, with its anterior margin, produced forward nearest the 
opisthotics; the exoccipitals well developed and contiguous above the foramen magnum; the vertebras 
in typical number (10+ 14) and longish; the anterior two partly coossified and the first with selliform 
apophyses extending backward and embracing the second vertebra; the vertebra? mostly with fovea? or 
pits for the ribs and only with developed parapophyses for the posterior (6 to 10) pairs of ribs; the 
second neural spine suberect, and with laminiform extensions, which embrace the first; neurapophyses 
and neural spines of other vertebra? depressed at their bases continuous with the zygapophyses in 
front, and slightly curved upward at their tips; the haemal spines resembling the neural.” 
Subocular laminae produced behind in a pointed process. External characters are the elongate 
body, with elevated back, straight abdomen, and angulated base of anal. Scales ctenoid, varying in 
size, lateral line conspicuous, extending on caudal tin, the tubes straight, confined to basal half of scale. 
Head depressed, pike-like, lower jaw projecting; villiform teeth, in bands, on jaws, vomer, and palatines; 
tongue smooth. Maxillary broad, truncate behind, with a strong supplemental bone. Pseudobranchiae 
present, small. Preopercle with a double ridge, posterior margin strongly serrated, with larger spines 
at angle; preorbital and suprascapula serrated, opercle without true spines. Gillrakers long. Dorsal 
fins well separated, first with 8 spines, first and second short, third and fourth longest; anal with 3 
spines, second strong, third long and slender, these fins moving in scaly sheaths. Caudal forked. 
Ventrals large, i, 5, inserted well behind pectorals, a scaly process at their base; pectorals narrow and 
rather pointed, upper rays longer than lower. Branchiostegals 7. Air-bladder well developed, simple, 
or with appendages anteriorly. 
This family comprises about 15 species, all American and referred to one genus. They are game- 
fishes, excellent as food. 
Genus 65. CENTROPOMUS Lacepede. The Robalos. 
The characters of this genus are included in the above. 
In American waters this genus contains 14 species, as recognized by Jordan & Evermann, only 2 of 
which are known from Porto Rico. All the species are of some value as food-fishes and some of them 
reach a large size. They occur on both coasts of tropical America and are fishes of shallow or moderate 
depths, two or three of them even ascending fresh-water streams for considerable distances. 
a. Preorbltal entire or very faintly serrated; spines of fins moderate, none more than half head; lateral line black, 
with about 70 scales (pores); caudal fin short; air-bladder usually with recurved appendages at its anterior 
end; anal with 6 soft rays, the last cleft to base. Size large. 
b. Appendages to air-bladder short, shorter than eye; second anal spine projecting beyond third unclecimalis, 102 
ad. Preorbital with well-developed retrorse teeth, especially posteriorly; air-bladder without appendages; spines 
longer. Size comparatively small. 
c. Lateral line in a narrow black streak. 
d. Scales moderate or large, 50 to 60 in lateral line; second anal spine very strong; ventrals more or less dusky, usually 
broadly tipped with black; anal rays in, 7, second spine a little shorter than third. 
e. Scales in lateral line 57 to 60 ; second anal spine very long, 1.25 to 1.60 in head ; depth of body 3.66 in 
length pedimactila 
re. Scales in lateral line 51 or 52; second anal spine 1.66 in head. Body more slender, the depth 3.75 in length. . cuvicri 
dd. Scales small, about 70 in lateral line; ventrals pale; second anal spine strong, equal to depth of body; anal rays 
in, 6 mexicanns 
cc. Lateral line pale, not in a dark stripe; ventral fins yellowish, without black tip. 
/. Scales very small, about 80; sides of body parallel with each other; second anal spine longer than third, equal to 
depth of body; anal rays nr, 7 parallelus, 103 
ff. Scales small, 65; second anal spine very long, about equal to depth of body; third anal spine same length; angle 
of preopercle with about 6 long, comb-like teeth; anal rays .in, 7 pectinatus 
///. Scales large, 19 to 53 in lateral line; eye moderate, about 6 in head; anal rays in, 6. 
g. Body moderately elongate, the depth 3.25 to 3.66 in length. 
A. Scales before dorsal small, 16 to 18 in number; maxillary reaching past front of pupil. Third dorsal spine half 
head; scales 51 armdtus 
hh. Scales before dorsal not crowded, 10 to 14 in number; maxillary barely reaching front of pupil; third dorsal spine 
less than half head; scales 7-53-11 affinis 
gg. Body more elongate, depth 4 in length; the second anal spine excessively long, 1.4 times depth of the body; 
scales 53 ensiferua 
F. C. B. 1900—10 
