尾索
Urochord \U"ro*chord\, n. [2d uro- + chord.] (Zo["o]l.) The central axis or cord in the tail of larval ascidians and of certain adult tunicates. [Written also {urocord}.]
urochord n 1: primitive marine animal having a saclike unsegmented body and a urochord (a notochord) conspicuous in the larva [syn: {tunicate}, {urochordate}] 2: a notochord of a larval tunicate typically confined to the caudal region