THE FISHES OF PORTO RICO. 
F. Anal preceded by 2 free spines (these lost with age; connected by membranes in the very youug) Carangtda;. 
FF. Anal without free spines. 
G. Dorsal and anal fins followed by finlets Scombrida:. 
GG. Dorsal and anal without finlets; mouth very large, nearly horizontal, the teeth sharp; no pseudobranchise. 
CHIASMODONTIDA). 
AA. Gill-openings small, behind, above, or below the pectoral fins, which are more or less pediculate. 
H. Gill-openings in or behind upper axil of pectoral; mouth small Ogcocephauda. 
IIH. Gill-openings in or behind lower axil of pectoral; mouth large. 
I. Head compressed; no pseudobranchise AntennariiD/e. 
II. Head depressed; pseudobranchise present Lophiida. 
III. — Ventral Fins Present, Thoracic or Jugular, Number of Rays not definitely I, 5. 
A. Eyes unsymmetrical, both on the same side of head. 
B. Eyes large, well separated; edge of preopercle usually evident Pleuronectida. 
BB. Eyes small, very close together; edge of preopercle hidden by skin; mouth very small Soi.eida:. 
A A. Eyes symmetrical, one on each side of the head. 
C. Ventral fin with or without spine, the number of soft rays more than 5. 
D. Caudal fin wanting; scales spinous , Macroitrida. 
DD. Caudal fin well developed. 
E. Ventral rays about 15; dorsal fin single, elevated Lampridida:. 
EE. Ventral rays 1 , 6 to 1 , 10; dorsal with spines. 
F. Chin with two long barbels behind symphysis; dorsal continuous, with 5 spines Polymixtjdas. 
FF. Chin without barbels. 
G. Dorsal fin divided, the anterior part of a single slender spine; ventrals elongate Bregmacerotida:. 
GG. Dorsal fin divided, the anterior part of many spines. 
H. Body covered with firm serrated scales; anal spines 4; dorsal spines not elevated Holocentrida. 
HH. Body naked or covered with small scales, besides bony plates or warts Zeidje. 
GGG. Dorsal fin continuous, its spines 2 to 8 Berycida:, 
CC. Ventral fin with or without spine, the number of soft rays fewer than 5. 
I. Gill-opening before the pectoral fin. 
J. Anal fin present; caudal fin not directed upward. 
K. Upper jaw not prolonged into a sword. 
L. Dorsal fin with some spines or simple rays. 
M. Dorsal fin without soft rays, composed of spines only Blenniida. 
MM. Dorsal fin with soft rays anteriorly, with spines posteriorly; gill-membranes joined to isthmus Zoarcida. 
MMM. Dorsal fin of spines anteriorly, with soft rays posteriorly. 
N. Suborbital with a bony stay, extending across cheek, to or toward preopercle, the cheek sometimes entirely covered 
with a coat of mail Cephalacanthid/e. 
NN. Suborbital without bony stay. 
O. Dorsal spines 2 to 4 only; head very broad, depressed; gills 3; gill-membranes broadly united to the isthmus. 
P. Ventrals each a strong spine; teeth incisor-like; scales shagreen-like Tpuacanthida:. 
PP. Ventrals not reduced each to a single spine Batrachoidida. 
00. Dorsal spines numerous; gills 4. 
Q. Gill-membranes separate, free from the isthmus. 
R. Body greatly elongate; lower jaw with a slit at base to permit, free motion; lips not fringed. 
S. Soft dorsal and anal with a distinct lobe anteriorly, distinct from spinous part Gempylida. 
SS. Soft dorsal and anal without anterior lobe, continuous with spinous part Lepidopodida. 
RR. Body moderately elongate; operclesand lips fringed; eyes superior Dactyloscopida. 
QQ. Gill-membranes broadly united, attached to the isthmus or not Blenniida. 
LL. Dorsal fins of soft rays only. 
T. Breast with a large sucking disk between ventral fins GoBiESOcroA. 
TT. Breast without sucking disk. 
U. Lateral line and base of dorsal beset with prickles; skeleton very soft; body compressed Icosteida. 
UU. Lateral line unarmed. 
V. Tail isocercal, the vertebral column pointed behind, the last vertebra very small; hypercoracoid not perforate; no 
pseudobran chi se . 
W. Caudal fin present Gadida. 
WVV. Caudal fin wanting Macrourid.e. 
VV. Tail not isocercal, truncate at base of caudal; hypercoracoid perforate. 
X. Gill-membranes joined to the isthmus; pseudobranchise present ZOarcida. 
XX. Gill-membranes free from the isthmus. 
Y. Ventral fins inserted below or before the eyes; pseudobranchise generally well developed Ophidiida. 
YY. Ventral fins inserted below shoulder-girdle; no pseudobranchise Brotulida. 
KK. Upper jaw prolonged into a bony sword; dorsal fin long and high; size large Istiophorida. 
J.T. Anal fin wanting; caudal fin distorted or directed upward; body ribbon-like; ventral fins each of a few slender 
rays Trach ypterida. 
II. Gill-opening behind the pectoral fin. 
Z. Gill-opening above and behind pectoral; mouth small, low Ogcocephalida. 
ZZ. Gill-opening below and behind pectoral; mouth large, nearly vertical Antennariida. 
