Archiannelida
原环虫纲
无脊椎
原环节动物
无脊椎
archiannelida[ noun ]
a class of Annelida
<noun.animal>
Archiannelida \Ar`chi*an*nel"i*da\, n. pl. [NL.; pref. archi- +
annelida.] (Zo["o]l.)
A group of Annelida remarkable for having no external
segments or distinct ventral nerve ganglions.