A SYSTEMATIC CATALOGUE OF THE FRESH WATER 
FISHES OF PANAMA. 
All of the fishes of the fresh waters of Panama belong to the class 
Pisces (fishes) and to the subclass Teleostomi (the true fishes), which 
possess a bony skeleton; a well developed skull; gill-opening a single 
slit on each side; nostrils at least two, not median; fins well developed, 
usually paired; alimentary canal more or less convoluted. 
KEY TO THE FAMILIES OF FRESH WATER FISHES OF PANAMA. 
a. Scales wanting, body smooth or with bony plates; one to 6 pairs 
of barbels or whiskers more or less developed about the mouth 
and nostrils. 
b. Body wholly naked (naked in Panama species) or with a single 
series of bony plates along side. 
c. Adipose fin present. 
d. Mouth terminal or subterminal; the lips not reverted and not 
forming a disc. Siluride, p. 239. 
dd. Mouth inferior; the lips reverted, forming an oval sucking disc. 
Cyclopide, p. 265. 
ce. Adipose fin wanting. Pygidiide, p. 266. 
bb. Body mostly or wholly covered with bony plates. 
e. Sides and back and often the ventral surface covered with bony 
plates; mouth wholly inferior; the lips reverted, forming a 
sucking disc. Loricariide, p. 246. 
ee. Sides with 2 series of bony plates; mouth terminal or subterminal; 
the lips not reverted nor developed into a sucking disc. 
Callichthyide, p. 263. 
aa. Scales usually present (present in all of the Panama species) ; no 
whiskers about the mouth and nostrils. 
f. Fins without spines. 
g. Body compressed or subterete, not eel-shaped; dorsal fin present. 
h. Adipose fin usually present (wanting in Phanagoniates and 
Hoplias); head naked, usually more or less compressed; lateral 
line complete or not (wanting in Piabucina). Characide, p. 267. 
hh. Adipose fin wanting; head partly scaly, usually depressed, flat 
above; lateral line wanting. Peciltide, p. 313. 
gg. Body more or less eel-shaped; dorsal fin wanting or represented 
by a mere filament. Gymnotida, p. 306. 
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