\Sym*bran"chi*i\, n. pl. [NL., fr. Gr. sy`n with + ?
a gill.] (Zo["o]l.)
An order of slender eel-like fishes having the gill openings
confluent beneath the neck. The pectoral arch is generally
attached to the skull, and the entire margin of the upper jaw
is formed by the premaxillary. Called also {Symbranchia}.