CLASS IV. ORDER. Si 
SYNBRANCHUS, (surinam-eel,) body eel-form ; 
pectoral fins none; spiracle single, beneath the 
neck. 
SPHAGEBRANCHUS, body eel-form ; pectoral fins 
none ; spiracles two, beneath the neck. 
Monoptrervus, body eel-form ; nosirils placed 
between the eyes ; fin caudal. 
Gymwotus, (electrical-eel,) head with lateral 
opercula ; tentacula two on the upper lip 3; eyes 
covered by the common skin; gill-membrane 5- 
rayed ; body compressed and carinated by a fin 
beneath. In most species no dorsal fin. 
Oruipium, (eel-fish,) head somewhat. naked, 
teeth in the jaws and palate and throat ; branchi- 
ostegous membrane 7-rayed, patulous; body en- 
siform. 
Ovontoenatuus, mouth furnished with a strong 
moveable lamina or process on each side of the 
upper jaw; gill-membrane 5-rayed. 
ComeEruorus, head large, with depressed snout: 
mouth large, with small teeth ; body elongated, 
compressed ; the second dorsal fin furnished with 
several long naked rays. 
Triurvs, (tripple-tail,) snout cylindric ; tooth 
~ single in each jaw ; fin, dorsal and anal, extend- 
ed beyond the tail. 
AmmopytTes, (launce,) head compressed, nar- 
rower than the body ; upper lip doubled ; lower 
jaw narrow, pointed ; teeth small and sharp ; gill- 
membrane 7-rayed ; body long, roundish, with 
very small scales ; tail distinct. 
LerrocerHA.us, (morris,) head small, narrow : 
body very thin, compressed ; pectoral fins none. 
StTyLepuorvs, (thread-tail,) eyes pedunculated, 
standing ona short thick cylinder ; snout length- 
