THE FISHES OF PORTO RICO. 
BB. Dorsal fin single, preceded by free spines. Body scaly; snout tubular Aulostomid®. 
BBB. Dorsal Jin composed of free spines; ventrals with 1 or 2 spines each; body elongate Notacanthid®. 
BBBB. Dorsal fins 2, the anterior of spines only, the posterior chiefly of soft rays. 
U. Pectoral fin with 5 to 8 lowermost rays detached and filamentous Polynemid®. 
UU. Pectoral fin entire. 
V. Teeth strong, unequal; lateral line present Sph yr®nid®. 
VV. Teeth small or wanting; lateral line obsolete. 
\Y. Dorsal spines 4, stout; anal spines 3 Mugilid®. 
YVW. Dorsal spines 4 to 8, slender; anal spine single Athekinid.e. 
A 
B. 
C. 
CC. 
D. 
E. 
EE. 
EEE. 
F. 
FF. 
DD 
G. 
GG. 
H. 
I. 
II, 
J. 
JJ. 
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ooo. 
p. 
pp. 
Q- 
QQ. 
R. 
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RR. 
T. 
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V. 
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UU. 
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II. — Ventral Fins Present, Thoracic or Subjugular, Number op Rays definitely I, 5. 
Gill-openings in front of the pectoral fins. 
Body more or less scaly or armed with bony plates. 
Ventral fins completely united; gill-membranes joined to the isthmus; no lateral line Gobiid®. 
Ventral fins separate. 
Suborbital with a bony stay, which extends across the cheek to or toward the preopercle; cheeks sometimes 
entirely mailed. 
Pectoral fin with 3 lower rays detached and free; head bony Triglid®. 
Pectoral fin with 2 lower rays detached and free; body mailed Peristediid®. 
Pectoral fin entire; slit behind fourth gill small or wanting. 
Dorsal spines 4; lips fringed; eyes superior Uranoscopid®. 
Dorsal spines 8 to 17; anal spines 3; body scaly Scorp.enid®. 
Suborbital stay wanting; cheeks not mailed. 
Spinous dorsal transformed into a sucking disk on top of head, composed of 8 to 30 transverse plates.. Echeneidid®. 
Spinous dorsal (if present) not transformed into a sucking disk. 
Dorsal spines all or nearly all disconnected from each other. 
Body elongate, spindle-shaped Rachycentrid®. 
Body oblong or ovate, compressed. 
Caudal peduncle very slender, the fin widely forked; preopercle entire Carangid®. 
Caudal peduncle stoutish, the fin little forked. Gill-membranes broadly united to isthmus Ephippid®. 
Dorsal spines (if present) all, or most of them, connected by membrane. 
Pectoral fin with 4 to 9 lowermost rays detached and filiform Polynemid®. 
Pectoral fin entire. 
Dorsal and anal each with 1 or more detached finlets. 
Anal preceded by 2 free spines Carangid®. 
Anal not preceded by 2 free spines. 
Caudal peduncle keeled Scombrid®. 
Caudal peduncle not keeled Gempylid®. 
Dorsal and anal without finlets. 
Lateral line armed posteriorly with a series of keeled plates; 2 free anal spines; gill-membranes free from isthmus. 
Carangid®. 
Lateral line armed posteriorly with a sharp, movable, lancet-like spine, or with a few bony tubercles; scales small, 
rough; gill-membranes adherent to isthmus Teuthidid®. 
Lateral line unarmed. 
Throat with 2 long barbels (placed just behind chin) ; dorsal fins 2 , Mullid®. 
Throat without long barbels. 
Anal fin preceded by 2 free spines (these obsolete in very old, joined by membrane in very young) ._... .Carangid®. 
Anal fin not preceded by free spines. 
Nostril single on each side; lateral line interrupted; lower pharyngeals united. 
Anal spines 2 Pomacentrid®. 
Anal spines 3 to 11. Fresh-water fishes Cichlid®. 
Nostril double on each side. 
Lateral line extending to tip of middle rays of caudal. 
Anal spines 3, the second strong. 
Dorsal fins 2, separate; body elongate Centropomid®. 
Dorsal fin continuous H.emui.td®. 
Anal spines 1 or 2, the second large or small Sci®nid®. 
Lateral line not extending beyond base of caudal fin. 
Gills 3.5, the slit behind the last very small or wanting. 
Mouth not vertical, lips not fringed; dorsal fin continuous, spines 8 to 18; scales cycloid; lower pharyngeals united. 
Teeth in each side of each jaw united, forming a sort of beak Scarid®. 
Teeth distinct or nearly so, the anterior usually more or less canine Labrid®. 
Mouth nearly vertical, the lips with fleshy fringes; dorsal divided, the spinous part short, of about 4 spines; lower 
pharyngeals separate Uranoscopid®. 
Gills 4, a long slit behind the fourth. 
Teeth setiform, like the teeth of a brush; body elevated, longer than deep, the soft fins completely scaled. 
Dorsal fin continuous Ch.ktodontid®. 
Dorsal fin divided Ephippid®. 
